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  • 1.
    Aartsen, M. G.
    et al.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Ackermann, M.
    DESY, D-15735 Zeuthen, Germany..
    Adams, J.
    Univ Canterbury, Dept Phys & Astron, Private Bag 4800, Christchurch, New Zealand..
    Aguilar, J. A.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Ahlers, M.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Ahrens, M.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Al Samarai, I.
    Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland..
    Altmann, D.
    Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Astroparticle Phys, D-91058 Erlangen, Germany..
    Andeen, K.
    Marquette Univ, Dept Phys, Milwaukee, WI 53201 USA..
    Anderson, T.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Ansseau, I.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Anton, G.
    Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Astroparticle Phys, D-91058 Erlangen, Germany..
    Archinger, M.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Arguelles, C.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Auffenberg, J.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Axani, S.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Bai, X.
    South Dakota Sch Mines & Technol, Phys Dept, Rapid City, SD 57701 USA..
    Barwick, S. W.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Baum, V.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Bay, R.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA..
    Beatty, J. J.
    Ohio State Univ, Dept Phys, Columbus, OH 43210 USA.;Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Columbus, OH 43210 USA.;Ohio State Univ, Dept Astron, Columbus, OH 43210 USA..
    Tjus, J. Becker
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Becker, K. -H
    BenZvi, S.
    Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA..
    Berley, D.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Bernardini, E.
    DESY, D-15735 Zeuthen, Germany..
    Bernhard, A.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Besson, D. Z.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Binder, G.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Bindig, D.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Blaufuss, E.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Blot, S.
    DESY, D-15735 Zeuthen, Germany..
    Bohm, C.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Boerner, M.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Bos, F.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Bose, D.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Boeser, S.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Botner, Olga
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Braun, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Brayeur, L.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Bretz, H. -P
    Bron, S.
    Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland..
    Burgman, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Carver, T.
    Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland..
    Casier, M.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Cheung, E.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Chirkin, D.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Christov, A.
    Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland..
    Clark, K.
    Univ Toronto, Dept Phys, 100 Coll St, Toronto, ON M5S 1A7, Canada..
    Classen, L.
    Westfal Wilhelms Univ Munster, Inst Kernphys, D-48149 Munster, Germany..
    Coenders, S.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Collin, G. H.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Conrad, J. M.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Cowen, D. F.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Cross, R.
    Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA..
    Day, M.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    de Andre, J. P. A. M.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    De Clercq, C.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Rosendo, E. del Pino
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Dembinski, H.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    De Ridder, S.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Desiati, P.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    de Vries, K. D.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    de Wasseige, G.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    de With, M.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany..
    DeYoung, T.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    di Lorenzo, V.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Dujmovic, H.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Dumm, J. P.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Dunkman, M.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Eberhardt, B.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Ehrhardt, T.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Eichmann, B.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Eller, P.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Euler, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Evenson, P. A.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Fahey, S.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Fazely, A. R.
    Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA..
    Feintzeig, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Felde, J.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Filimonov, K.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA..
    Finley, C.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Flis, S.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Foesig, C. -C
    Franckowiak, A.
    DESY, D-15735 Zeuthen, Germany..
    Friedman, E.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Fuchs, T.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Gaisser, T. K.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Gallagher, J.
    Univ Wisconsin, Dept Astron, Madison, WI 53706 USA..
    Gerhardt, L.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Ghorbani, K.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Giang, W.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Gladstone, L.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Glauch, T.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Gluesekamp, T.
    Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Astroparticle Phys, D-91058 Erlangen, Germany..
    Goldschmidt, A.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Gonzalez, J. G.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Grant, D.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Griffith, Z.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Haack, C.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Hallgren, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Halzen, F.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Hansen, E.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark..
    Hansmann, T.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Hanson, K.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Hebecker, D.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany..
    Heereman, D.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Helbing, K.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Hellauer, R.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Hickford, S.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Hignight, J.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Hill, G. C.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Hoffman, K. D.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Hoffmann, R.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Hoshina, K.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA.;Univ Tokyo, Earthquake Res Inst, Bunkyo Ku, Tokyo 1130032, Japan..
    Huang, F.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Huber, M.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Hultqvist, K.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    In, S.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Ishihara, A.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Jacobi, E.
    DESY, D-15735 Zeuthen, Germany..
    Japaridze, G. S.
    Clark Atlanta Univ, CTSPS, Atlanta, GA 30314 USA..
    Jeong, M.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Jero, K.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Jones, B. J. P.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Kang, W.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Kappes, A.
    Westfal Wilhelms Univ Munster, Inst Kernphys, D-48149 Munster, Germany..
    Karg, T.
    DESY, D-15735 Zeuthen, Germany..
    Karle, A.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Katz, U.
    Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Astroparticle Phys, D-91058 Erlangen, Germany..
    Kauer, M.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Keivani, A.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Kelley, J. L.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Kheirandish, A.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Kim, J.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Kim, M.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Kintscher, T.
    DESY, D-15735 Zeuthen, Germany..
    Kiryluk, J.
    SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA..
    Kittler, T.
    Klein, S. R.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Kohnen, G.
    Univ Mons, B-7000 Mons, Belgium..
    Koirala, R.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Kolanoski, H.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany..
    Konietz, R.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Koepke, L.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Kopper, C.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Kopper, S.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Koskinen, D. J.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark..
    Kowalski, M.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany.;DESY, D-15735 Zeuthen, Germany..
    Krings, K.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Kroll, M.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Krueckl, G.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Krueger, C.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Kunnen, J.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Kunwar, S.
    DESY, D-15735 Zeuthen, Germany..
    Kurahashi, N.
    Drexel Univ, Dept Phys, 3141 Chestnut St, Philadelphia, PA 19104 USA..
    Kuwabara, T.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Kyriacou, A.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Labare, M.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Lanfranchi, J. L.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Larson, M. J.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark..
    Lauber, F.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Lesiak-Bzdak, M.
    SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA..
    Leuermann, M.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Lu, L.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Luenemann, J.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Madsen, J.
    Univ Wisconsin, Dept Phys, River Falls, WI 54022 USA..
    Maggi, G.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Mahn, K. B. M.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Mancina, S.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Mandelartz, M.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Maruyama, R.
    Yale Univ, Dept Phys, New Haven, CT 06520 USA..
    Mase, K.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Maunu, R.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    McNally, F.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Meagher, K.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Medici, M.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark..
    Meier, M.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Menne, T.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Merino, G.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Meures, T.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Miarecki, S.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Micallef, J.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Momente, G.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Montaruli, T.
    Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland..
    Moulai, M.
    MIT, Dept Phys, Cambridge, MA 02139 USA..
    Nahnhauer, R.
    DESY, D-15735 Zeuthen, Germany..
    Naumann, U.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Neer, G.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Niederhausen, H.
    SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA..
    Nowicki, S. C.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Nygren, D. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Pollmann, A. Obertacke
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Olivas, A.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    O'Murchadha, A.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Palczewski, T.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Pandya, H.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Pankova, D. V.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Peiffer, P.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Penek, O.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Pepper, J. A.
    Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA..
    de los Heros, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Pieloth, D.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Pinat, E.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Price, P. B.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA..
    Przybylski, G. T.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Quinnan, M.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Raab, C.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Raedel, L.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Rameez, M.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark..
    Rawlins, K.
    Univ Alaska Anchorage, Dept Phys & Astron, 3211 Providence Dr, Anchorage, AK 99508 USA..
    Reimann, R.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Relethford, B.
    Drexel Univ, Dept Phys, 3141 Chestnut St, Philadelphia, PA 19104 USA..
    Relich, M.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Resconi, E.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Rhode, W.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Richman, M.
    Drexel Univ, Dept Phys, 3141 Chestnut St, Philadelphia, PA 19104 USA..
    Riedel, B.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Robertson, S.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Rongen, M.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Rott, C.
    Sungkyunkwan Univ, Dept Phys, Suwon 440746, South Korea..
    Ruhe, T.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Ryckbosch, D.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Rysewyk, D.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Sabbatini, L.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Herrera, S. E. Sanchez
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Sandrock, A.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Sandroos, J.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Sarkar, S.
    Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark.;Univ Oxford, Dept Phys, Oxford OX1 3NP, England..
    Satalecka, K.
    DESY, D-15735 Zeuthen, Germany..
    Schlunder, P.
    TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany..
    Schmidt, T.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Schoenen, S.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Schoeneberg, S.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Schumacher, L.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Seckel, D.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Seunarine, S.
    Univ Wisconsin, Dept Phys, River Falls, WI 54022 USA..
    Soldin, D.
    Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany..
    Song, M.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Spiczak, G. M.
    Univ Wisconsin, Dept Phys, River Falls, WI 54022 USA..
    Spiering, C.
    DESY, D-15735 Zeuthen, Germany..
    Stachurska, J.
    DESY, D-15735 Zeuthen, Germany..
    Stanev, T.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Stasik, A.
    DESY, D-15735 Zeuthen, Germany..
    Stettner, J.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Steuer, A.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Stezelberger, T.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Stokstad, R. G.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Stoessl, A.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Ström, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Strotjohann, N. L.
    DESY, D-15735 Zeuthen, Germany..
    Sullivan, G. W.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Sutherland, M.
    Ohio State Univ, Dept Phys, Columbus, OH 43210 USA.;Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Columbus, OH 43210 USA..
    Taavola, Henric
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Taboada, I.
    Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA.;Georgia Inst Technol, Ctr Relativist Astrophys, Atlanta, GA 30332 USA..
    Tatar, J.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Tenholt, F.
    Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany..
    Ter-Antonyan, S.
    Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA..
    Terliuk, A.
    DESY, D-15735 Zeuthen, Germany..
    Tesic, G.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Tilav, S.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Toale, P. A.
    Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA..
    Tobin, M. N.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Toscano, S.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Tosi, D.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Tselengidou, M.
    Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Astroparticle Phys, D-91058 Erlangen, Germany..
    Tung, C. F.
    Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA.;Georgia Inst Technol, Ctr Relativist Astrophys, Atlanta, GA 30332 USA..
    Turcati, A.
    Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Unger, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Usner, M.
    DESY, D-15735 Zeuthen, Germany..
    Vandenbroucke, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    van Eijndhoven, N.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Vanheule, S.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    van Rossem, M.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    van Santen, J.
    DESY, D-15735 Zeuthen, Germany..
    Vehring, M.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Voge, M.
    Univ Bonn, Phys Inst, Nussallee 12, D-53115 Bonn, Germany..
    Vogel, E.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Vraeghe, M.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Walck, C.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Wallace, A.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Wallraff, M.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Wandkowsky, N.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Waza, A.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Weaver, Ch.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Weiss, M. J.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Wendt, C.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Westerhoff, S.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Whelan, B. J.
    Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
    Wickmann, S.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Wiebe, K.
    Johannes Gutenberg Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany..
    Wiebusch, C. H.
    Rhein Westfal TH Aachen, Phys Inst 3, D-52056 Aachen, Germany..
    Wille, L.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Williams, D. R.
    Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA..
    Wills, L.
    Drexel Univ, Dept Phys, 3141 Chestnut St, Philadelphia, PA 19104 USA..
    Wolf, M.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Wood, T. R.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Woolsey, E.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Woschnagg, K.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA..
    Xu, D. L.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Xu, X. W.
    Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA..
    Xu, Y.
    SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA..
    Yanez, J. P.
    Univ Alberta, Dept Phys, Edmonton, AB T6G 2E1, Canada..
    Yodh, G.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Yoshida, S.
    Chiba Univ, Dept Phys, Chiba 2638522, Japan.;Chiba Univ, Inst Global Prominent Res, Chiba 2638522, Japan..
    Zoll, M.
    Stockholm Univ, Oskar Klein Ctr, S-10691 Stockholm, Sweden.;Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden..
    Stanek, K. Z.
    Ohio State Univ, Dept Phys, Columbus, OH 43210 USA.;Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Columbus, OH 43210 USA.;Ohio State Univ, Dept Astron, Columbus, OH 43210 USA..
    Shappee, B. J.
    Carnegie Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA..
    Kochanek, C. S.
    Ohio State Univ, Dept Phys, Columbus, OH 43210 USA.;Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Columbus, OH 43210 USA.;Ohio State Univ, Dept Astron, Columbus, OH 43210 USA..
    Holoien, T. W. -S
    Prieto, J. L.
    Univ Diego Port, Nucl Astron Fac Ingn, Av Ejercito 441, Santiago, Chile.;Millennium Inst Astrophys, Santiago, Chile..
    Fox, D. B.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Theoret & Observat Cosmol, University Pk, PA 16802 USA..
    DeLaunay, J. J.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA..
    Turley, C. F.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA..
    Barthelmy, S. D.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Lien, A. Y.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Meszaros, P.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Dept Phys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Theoret & Observat Cosmol, University Pk, PA 16802 USA..
    Murase, K.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Dept Phys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA.;Penn State Univ, Inst Gravitat & Cosmos, Ctr Theoret & Observat Cosmol, University Pk, PA 16802 USA..
    Kocevski, D.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Buehler, R.
    DESY, D-15735 Zeuthen, Germany..
    Giomi, M.
    DESY, D-15735 Zeuthen, Germany..
    Racusin, J. L.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Albert, A.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA.;Tech Univ Munich, Phys Dept, D-85748 Garching, Germany..
    Alfaro, R.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Alvarez, C.
    Univ Autonoma Chiapas, Tuxtla Gutierrez, Chiapas, Mexico..
    Alvarez, J. D.
    Univ Michoacana, Morelia, Michoacan, Mexico..
    Arceo, R.
    Univ Autonoma Chiapas, Tuxtla Gutierrez, Chiapas, Mexico..
    Arteaga-Velazquez, J. C.
    Univ Michoacana, Morelia, Michoacan, Mexico..
    Solares, H. A. Ayala
    Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA..
    Barber, A. S.
    Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA..
    Baustista-Elivar, N.
    Univ Politecn Pachuca, Pachuca, Hgo, Mexico..
    Becerril, A.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Belmont-Moreno, E.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Bernal, A.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany.;Univ Nacl Autonoma Mexico, Inst Astron, Mexico City, DF, Mexico..
    Brisbois, C.
    Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA..
    Caballero-Mora, K. S.
    Univ Autonoma Chiapas, Tuxtla Gutierrez, Chiapas, Mexico..
    Capistran, T.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    Carraminana, A.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    Casanova, S.
    Henryka Niewodniczanskiego Polskiej Akad Nauk, Inst Fizyki Jadrowej, IFJ PAN, PL-31342 Krakow, Poland..
    Castillo, M.
    Univ Michoacana, Morelia, Michoacan, Mexico..
    Cotti, U.
    Univ Michoacana, Morelia, Michoacan, Mexico..
    Coutino de Leon, S.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    de la Fuente, E.
    Univ Guadalajara, Ctr Univ Ciencias Exactase Ingenierias, Dept Fis, Guadalajara, Mexico..
    De Leon, C.
    Benemerita Univ Autonoma Puebla, Fac Ciencias Fis, Puebla, Mexico..
    Diaz Hernandez, R.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    Diaz-Velez, J. C.
    Univ Guadalajara, Ctr Univ Ciencias Exactase Ingenierias, Dept Fis, Guadalajara, Mexico.;Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Dingus, B. L.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA..
    DuVernois, M. A.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Ellsworth, R. W.
    George Mason Univ, Sch Phys Astron & Computat Sci, Fairfax, VA USA..
    Engel, K.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Fiorino, D. W.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Fraija, N.
    Univ Nacl Autonoma Mexico, Inst Astron, Mexico City, DF, Mexico..
    Garcia-Gonzalez, J. A.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Gerhardt, M.
    Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA..
    Gonzalez Munoz, A.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Gonzalez, M. M.
    Univ Nacl Autonoma Mexico, Inst Astron, Mexico City, DF, Mexico..
    Goodman, J. A.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Hampel-Arias, Z.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Harding, J. P.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA..
    Hernandez, S.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Hui, C. M.
    NASA, Marshall Space Flight Ctr, Astrophys Off, Huntsville, AL 35812 USA..
    Huentemeyer, P.
    Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA..
    Iriarte, A.
    Univ Nacl Autonoma Mexico, Inst Astron, Mexico City, DF, Mexico..
    Jardin-Blicq, A.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Joshi, V.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Kaufmann, S.
    Univ Autonoma Chiapas, Tuxtla Gutierrez, Chiapas, Mexico..
    Lara, A.
    Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City, DF, Mexico..
    Lauer, R. J.
    Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA..
    Lee, W. H.
    Univ Nacl Autonoma Mexico, Inst Astron, Mexico City, DF, Mexico..
    Lennarz, D.
    Clark Atlanta Univ, CTSPS, Atlanta, GA 30314 USA..
    Leon Vargas, H.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Linnemann, J. T.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Luis Raya, G.
    Univ Politecn Pachuca, Pachuca, Hgo, Mexico..
    Luna-Garcia, R.
    Inst Politecn Nacl, Ctr Invest Computac, Mexico City, DF, Mexico..
    Lopez-Coto, R.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Malone, K.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Marinelli, S. S.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Martinez, O.
    Benemerita Univ Autonoma Puebla, Fac Ciencias Fis, Puebla, Mexico..
    Martinez-Castellanos, I.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Martinez-Castro, J.
    Inst Politecn Nacl, Ctr Invest Computac, Mexico City, DF, Mexico..
    Martinez-Huerta, H.
    Ctr Invest & Estudios Avanzados IPN, Phys Dept, Mexico City, DF, Mexico..
    Matthews, J. A.
    Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA..
    Miranda-Romagnoli, P.
    Univ Autonoma Estado Hidalgo, Pachuca, Mexico..
    Moreno, E.
    Benemerita Univ Autonoma Puebla, Fac Ciencias Fis, Puebla, Mexico..
    Mostafa, M.
    Penn State Univ, Dept Phys, University Pk, PA 16802 USA..
    Nellen, L.
    Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Mexico City, DF, Mexico..
    Newbold, M.
    Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA..
    Nisa, M. U.
    Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA..
    Noriega-Papaqui, R.
    Univ Autonoma Estado Hidalgo, Pachuca, Mexico..
    Pelayo, R.
    Inst Politecn Nacl, Ctr Invest Computac, Mexico City, DF, Mexico..
    Pretz, J.
    Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA..
    Perez-Perez, E. G.
    Univ Politecn Pachuca, Pachuca, Hgo, Mexico..
    Ren, Z.
    Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA..
    Rho, C. D.
    Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA..
    Riviere, C.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Rosa-Gonzalez, D.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    Rosenberg, M.
    Penn State Univ, Inst Gravitat & Cosmos, Ctr Particle & Gravitat Astrophys, University Pk, PA 16802 USA..
    Greus, F. Salesa
    Henryka Niewodniczanskiego Polskiej Akad Nauk, Inst Fizyki Jadrowej, IFJ PAN, PL-31342 Krakow, Poland..
    Sandoval, A.
    Univ Nacl Autonoma Mexico, Inst Fis, Mexico City, DF, Mexico..
    Schneider, M.
    Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA.;Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA..
    Schoorlemmer, H.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Sinnis, G.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA..
    Smith, A. J.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Springer, R. W.
    Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA..
    Surajbali, P.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Tibolla, O.
    Univ Autonoma Chiapas, Tuxtla Gutierrez, Chiapas, Mexico..
    Tollefson, K.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Torres, I.
    Inst Nacl Astrofis Opt & Electr, Puebla, Mexico..
    Ukwatta, T. N.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA..
    Villasenor, L.
    Univ Michoacana, Morelia, Michoacan, Mexico..
    Weisgarber, T.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Wisher, I. G.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Wood, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA.;Univ Wisconsin, Wisconsin IceCube Particle Astrophys, Madison, WI 53706 USA..
    Yapici, T.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Zepeda, A.
    Ctr Invest & Estudios Avanzados IPN, Phys Dept, Mexico City, DF, Mexico..
    Zhou, H.
    Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA..
    Arcavi, I.
    Las Cumbres Observ, 6740 Cortona Dr,Ste 102, Goleta, CA 93117 USA.;Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA.;Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA..
    Hosseinzadeh, G.
    Las Cumbres Observ, 6740 Cortona Dr,Ste 102, Goleta, CA 93117 USA.;Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA..
    Howell, D. A.
    Las Cumbres Observ, 6740 Cortona Dr,Ste 102, Goleta, CA 93117 USA.;Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA..
    Valenti, S.
    Univ Calif, Dept Phys, 1 Shields Ave, Davis, CA 95616 USA..
    McCully, C.
    Las Cumbres Observ, 6740 Cortona Dr,Ste 102, Goleta, CA 93117 USA.;Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA..
    Lipunov, V. M.
    Lomonosov Moscow State Univ, Phys Dept, Leninskie Gory GSP 1, Moscow 119991, Russia.;Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Gorbovskoy, E. S.
    Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Tiurina, N. V.
    Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Balanutsa, P. V.
    Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Kuznetsov, A. S.
    Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Kornilov, V. G.
    Lomonosov Moscow State Univ, Phys Dept, Leninskie Gory GSP 1, Moscow 119991, Russia.;Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Chazov, V.
    Lomonosov Moscow State Univ, Sternberg Astron Inst, Univ Prospekt 13, Moscow 119192, Russia..
    Budnev, N. M.
    Irkutsk State Univ, Inst Appl Phys, 20 Gagarin Blvd, Irkutsk 664003, Russia..
    Gress, O. A.
    Irkutsk State Univ, Inst Appl Phys, 20 Gagarin Blvd, Irkutsk 664003, Russia..
    Ivanov, K. I.
    Irkutsk State Univ, Inst Appl Phys, 20 Gagarin Blvd, Irkutsk 664003, Russia..
    Tlatov, A. G.
    Main Pulkovo Observ, Kislovodsk Solar Stn, POB 45,Gagarina 100, Kislovodsk 357700, Russia..
    Lopez, R. Rebolo
    Inst Astrofis Canarias, Observ Teide, Via Lactea S-N, Tenerife 38205, Spain..
    Serra-Ricart, M.
    Inst Astrofis Canarias, Observ Teide, Via Lactea S-N, Tenerife 38205, Spain..
    Evans, P. A.
    Univ Leicester, Leicester Inst Space & Earth Observ, Dept Phys & Astron, Xray & Observat Astron Res Grp, Univ Rd, Leicester LE1 7RH, Leics, England..
    Kennea, J. A.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA..
    Gehrels, N.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Osborne, J. P.
    Univ Leicester, Leicester Inst Space & Earth Observ, Dept Phys & Astron, Xray & Observat Astron Res Grp, Univ Rd, Leicester LE1 7RH, Leics, England..
    Page, K. L.
    Univ Leicester, Leicester Inst Space & Earth Observ, Dept Phys & Astron, Xray & Observat Astron Res Grp, Univ Rd, Leicester LE1 7RH, Leics, England..
    Abeysekara, A. U.
    Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA..
    Archer, A.
    Washington Univ, Dept Phys, St Louis, MO 63130 USA..
    Benbow, W.
    Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA..
    Bird, R.
    Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA..
    Brantseg, T.
    Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA..
    Bugaev, V.
    Washington Univ, Dept Phys, St Louis, MO 63130 USA..
    Cardenzana, J. V.
    Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA..
    Connolly, M. P.
    Natl Univ Ireland Galway, Sch Phys, Univ Rd, Galway, Ireland..
    Cui, W.
    Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China.;Tsinghua Univ, Ctr Astrophys, Beijing 100084, Peoples R China.;Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA..
    Falcone, A.
    Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA..
    Feng, Q.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    Finley, J. P.
    Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA..
    Fleischhack, H.
    DESY, D-15735 Zeuthen, Germany..
    Fortson, L.
    Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA..
    Furniss, A.
    Calif State Univ East Bay, Dept Phys, Hayward, CA 94542 USA..
    Griffin, S.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada.;Washington Univ, Dept Phys, St Louis, MO 63130 USA..
    Grube, J.
    Stevens Inst Technol, Dept Phys, Hoboken, NJ 07030 USA..
    Huetten, M.
    DESY, D-15735 Zeuthen, Germany..
    Hervet, O.
    Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA.;Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA..
    Holder, J.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Hughes, G.
    Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA..
    Humensky, T. B.
    Columbia Univ, Phys Dept, New York, NY 10027 USA..
    Johnson, C. A.
    Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA.;Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA..
    Kaaret, P.
    Univ Iowa, Dept Phys & Astron, Allen Hall, Iowa City, IA 52242 USA..
    Kar, P.
    Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA..
    Kelley-Hoskins, N.
    DESY, D-15735 Zeuthen, Germany..
    Kertzman, M.
    Depauw Univ, Dept Phys & Astron, Greencastle, IN 46135 USA..
    Krause, M.
    DESY, D-15735 Zeuthen, Germany..
    Kumar, S.
    Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.;Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Lang, M. J.
    Natl Univ Ireland Galway, Sch Phys, Univ Rd, Galway, Ireland..
    Lin, T. T. Y.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    McArthur, S.
    Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA..
    Moriarty, P.
    Natl Univ Ireland Galway, Sch Phys, Univ Rd, Galway, Ireland..
    Mukherjee, R.
    Columbia Univ, Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA..
    Nieto, D.
    Columbia Univ, Phys Dept, New York, NY 10027 USA..
    Ong, R. A.
    Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA..
    Otte, A. N.
    Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA.;Georgia Inst Technol, Ctr Relativist Astrophys, Atlanta, GA 30332 USA..
    Pohl, M.
    Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany.;DESY, D-15735 Zeuthen, Germany..
    Popkow, A.
    Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA..
    Pueschel, E.
    Univ Coll Dublin, Sch Phys, Dublin 4, Ireland..
    Quinn, J.
    Univ Coll Dublin, Sch Phys, Dublin 4, Ireland..
    Ragan, K.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    Reynolds, P. T.
    Cork Inst Technol, Dept Phys Sci, Cork, Ireland..
    Richards, G. T.
    Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA.;Georgia Inst Technol, Ctr Relativist Astrophys, Atlanta, GA 30332 USA..
    Roache, E.
    Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA..
    Rulten, C.
    Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA..
    Sadeh, I.
    DESY, D-15735 Zeuthen, Germany..
    Santander, M.
    Columbia Univ, Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA..
    Sembroski, G. H.
    Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA..
    Staszak, D.
    Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA..
    Trepanier, S.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    Tyler, J.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    Wakely, S. P.
    Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA..
    Weinstein, A.
    Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA..
    Wilcox, P.
    Univ Iowa, Dept Phys & Astron, Allen Hall, Iowa City, IA 52242 USA..
    Wilhelm, A.
    Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany.;DESY, D-15735 Zeuthen, Germany..
    Williams, D. A.
    Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA.;Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA..
    Zitzer, B.
    McGill Univ, Phys Dept, Montreal, PQ H3A 2T8, Canada..
    Bellm, E.
    CALTECH, Cahill Ctr Astron & Astrophys, Pasadena, CA 91125 USA..
    Cano, Z.
    CSIC, IAA, Glorieta Astron S-N, E-18008 Granada, Spain..
    Gal-Yam, A.
    Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-7610001 Rehovot, Israel..
    Kann, D. A.
    Thuringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany..
    Ofek, E. O.
    Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-7610001 Rehovot, Israel..
    Rigault, M.
    Humboldt Univ, Inst Phys, D-12489 Berlin, Germany..
    Soumagnac, M.
    Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-7610001 Rehovot, Israel..
    Multiwavelength follow-up of a rare IceCube neutrino multiplet2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 607, article id A115Article in journal (Refereed)
    Abstract [en]

    On February 17, 2016, the IceCube real-time neutrino search identified, for the first time, three muon neutrino candidates arriving within 100 s of one another, consistent with coming from the same point in the sky. Such a triplet is expected once every 13.7 years as a random coincidence of background events. However, considering the lifetime of the follow-up program the probability of detecting at least one triplet from atmospheric background is 32%. Follow-up observatories were notified in order to search for an electromagnetic counterpart. Observations were obtained by Swift's X-ray telescope, by ASAS-SN, LCO and MASTER at optical wavelengths, and by VERITAS in the very-high-energy gamma-ray regime. Moreover, the Swift BAT serendipitously observed the location 100 s after the first neutrino was detected, and data from the Fermi LAT and HAWC observatory were analyzed. We present details of the neutrino triplet and the follow-up observations. No likely electromagnetic counterpart was detected, and we discuss the implications of these constraints on candidate neutrino sources such as gamma-ray bursts, core-collapse supernovae and active galactic nucleus flares. This study illustrates the potential of and challenges for future follow-up campaigns.

  • 2. Abbasi, R.
    et al.
    Abdou, Y.
    Abu-Zayyad, T.
    Ackermann, M.
    Adams, J.
    Aguilar, J. A.
    Ahlers, M.
    Allen, M. M.
    Altmann, D.
    Andeen, K.
    Auffenberg, J.
    Bai, X.
    Baker, M.
    Barwick, S. W.
    Baum, V.
    Bay, R.
    Alba, J. L. Bazo
    Beattie, K.
    Beatty, J. J.
    Bechet, S.
    Becker, J. K.
    Becker, K. -H
    Benabderrahmane, M. L.
    BenZvi, S.
    Berdermann, J.
    Berghaus, P.
    Berley, D.
    Bernardini, E.
    Bertrand, D.
    Besson, D. Z.
    Bindig, D.
    Bissok, M.
    Blaufuss, E.
    Blumenthal, J.
    Boersma, D. J.
    Bohm, C.
    Bose, D.
    Boeser, S.
    Botner, Olga
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Brown, A. M.
    Buitink, S.
    Caballero-Mora, K. S.
    Carson, M.
    Chirkin, D.
    Christy, B.
    Clevermann, F.
    Cohen, S.
    Colnard, C.
    Cowen, D. F.
    Silva, A. H. Cruz
    D'Agostino, M. V.
    Danninger, M.
    Daughhetee, J.
    Davis, J. C.
    De Clercq, C.
    Degner, T.
    Demiroers, L.
    Descamps, F.
    Desiati, P.
    de Vries-Uiterweerd, G.
    DeYoung, T.
    Diaz-Velez, J. C.
    Dierckxsens, M.
    Dreyer, J.
    Dumm, J. P.
    Dunkman, M.
    Eisch, J.
    Ellsworth, R. W.
    Engdegård, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Euler, S.
    Evenson, P. A.
    Fadiran, O.
    Fazely, A. R.
    Fedynitch, A.
    Feintzeig, J.
    Feusels, T.
    Filimonov, K.
    Finley, C.
    Fischer-Wasels, T.
    Fox, B. D.
    Franckowiak, A.
    Franke, R.
    Gaisser, T. K.
    Gallagher, J.
    Gerhardt, L.
    Gladstone, L.
    Gluesenkamp, T.
    Goldschmidt, A.
    Goodman, J. A.
    Gora, D.
    Grant, D.
    Griesel, T.
    Gross, A.
    Grullon, S.
    Gurtner, M.
    Ha, C.
    Ismail, A. Haj
    Hallgren, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Halzen, F.
    Han, K.
    Hanson, K.
    Heinen, D.
    Helbing, K.
    Hellauer, R.
    Hickford, S.
    Hill, G. C.
    Hoffman, K. D.
    Hoffmann, B.
    Homeier, A.
    Hoshina, K.
    Huelsnitz, W.
    Huelss, J. -P
    Hulth, P. O.
    Hultqvist, K.
    Hussain, S.
    Ishihara, A.
    Jakobi, E.
    Jacobsen, J.
    Japaridze, G. S.
    Johansson, H.
    Kampert, K. -H
    Kappes, A.
    Karg, T.
    Karle, A.
    Kenny, P.
    Kiryluk, J.
    Kislat, F.
    Klein, S. R.
    Koehne, H.
    Kohnen, G.
    Kolanoski, H.
    Koepke, L.
    Kopper, S.
    Koskinen, D. J.
    Kowalski, M.
    Kowarik, T.
    Krasberg, M.
    Kroll, G.
    Kurahashi, N.
    Kuwabara, T.
    Labare, M.
    Laihem, K.
    Landsman, H.
    Larson, M. J.
    Lauer, R.
    Luenemann, J.
    Madsen, J.
    Marotta, A.
    Maruyama, R.
    Mase, K.
    Matis, H. S.
    Meagher, K.
    Merck, M.
    Meszaros, P.
    Meures, T.
    Miarecki, S.
    Middell, E.
    Milke, N.
    Miller, J
    Montaruli, T.
    Morse, R.
    Movit, S. M.
    Nahnhauer, R.
    Nam, J. W.
    Naumann, U.
    Nygren, D. R.
    Odrowski, S.
    Olivas, A.
    Olivo, Martino
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    O'Murchadha, A.
    Panknin, S.
    Paul, L.
    Pérez de los Heros, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Petrovic, J.
    Piegsa, A.
    Pieloth, D.
    Porrata, R.
    Posselt, J.
    Price, P. B.
    Przybylski, G. T.
    Rawlins, K.
    Redl, P.
    Resconi, E.
    Rhode, W.
    Ribordy, M.
    Richard, A. S.
    Richman, M.
    Rodrigues, J. P.
    Rothmaier, F.
    Rott, C.
    Ruhe, T.
    Rutledge, D.
    Ruzybayev, B.
    Ryckbosch, D.
    Sander, H. -G
    Santander, M.
    Sarkar, S.
    Schatto, K.
    Schmidt, T.
    Schoenwald, A.
    Schukraft, A.
    Schulte, L.
    Schultes, A.
    Schulz, O.
    Schunck, M.
    Seckel, D.
    Semburg, B.
    Seo, S. H.
    Sestayo, Y.
    Seunarine, S.
    Silvestri, A.
    Singh, K.
    Slipak, A.
    Spiczak, G. M.
    Spiering, C.
    Stamatikos, M.
    Stanev, T.
    Stezelberger, T.
    Stokstad, R. G.
    Stoessl, A.
    Strahler, E. A.
    Ström, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Stueer, M.
    Sullivan, G. W.
    Swillens, Q.
    Taavola, Henric
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Taboada, I.
    Tamburro, A.
    Tepe, A.
    Ter-Antonyan, S.
    Tilav, S.
    Toale, P. A.
    Toscano, S.
    Tosi, D.
    van Eijndhoven, N.
    Vandenbroucke, J.
    Van Overloop, A.
    van Santen, J.
    Vehring, M.
    Voge, M.
    Walck, C.
    Waldenmaier, T.
    Wallraff, M.
    Walter, M.
    Weaver, Ch.
    Wendt, C.
    Westerhoff, S.
    Whitehorn, N.
    Wiebe, K.
    Wiebusch, C. H.
    Williams, D. R.
    Wischnewski, R.
    Wissing, H.
    Wolf, M.
    Wood, T. R.
    Woschnagg, K.
    Xu, C.
    Xu, D. L.
    Xu, X. W.
    Yanez, J. P.
    Yodh, G.
    Yoshida, S.
    Zarzhitsky, P.
    Zoll, M.
    IceCube sensitivity for low-energy neutrinos from nearby supernovae2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 535, p. A109-Article in journal (Refereed)
    Abstract [en]

    This paper describes the response of the IceCube neutrino telescope located at the geographic south pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of similar to 1 km(3) in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak of nu(e)'s released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.

  • 3. Abbasi, R.
    et al.
    Abdou, Y.
    Abu-Zayyad, T.
    Ackermann, M.
    Adams, J.
    Aguilar, J. A.
    Ahlers, M.
    Allen, M. M.
    Altmann, D.
    Andeen, K.
    Auffenberg, J.
    Bai, X.
    Baker, M.
    Barwick, S. W.
    Bay, R.
    Alba, J. L. Bazo
    Beattie, K.
    Beatty, J. J.
    Bechet, S.
    Becker, J. K.
    Becker, K. -H
    Benabderrahmane, M. L.
    BenZvi, S.
    Berdermann, J.
    Berghaus, P.
    Berley, D.
    Bernardini, E.
    Bertrand, D.
    Besson, D. Z.
    Bindig, D.
    Bissok, M.
    Blaufuss, E.
    Blumenthal, J.
    Boersma, D. J.
    Bohm, C.
    Bose, D.
    Boeser, S.
    Botner, Olga
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Brown, A. M.
    Buitink, S.
    Caballero-Mora, K. S.
    Carson, M.
    Chirkin, D.
    Christy, B.
    Clevermann, F.
    Cohen, S.
    Colnard, C.
    Cowen, D. F.
    Silva, A. H. Cruz
    D'Agostino, M. V.
    Danninger, M.
    Daughhetee, J.
    Davis, J. C.
    De Clercq, C.
    Degner, T.
    Demiroers, L.
    Descamps, F.
    Desiati, P.
    de Vries-Uiterweerd, G.
    DeYoung, T.
    Diaz-Velez, J. C.
    Dierckxsens, M.
    Dreyer, J.
    Dumm, J. P.
    Dunkman, M.
    Eisch, J.
    Ellsworth, R. W.
    Engdegård, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Euler, S.
    Evenson, P. A.
    Fadiran, O.
    Fazely, A. R.
    Fedynitch, A.
    Feintzeig, J.
    Feusels, T.
    Filimonov, K.
    Finley, C.
    Fischer-Wasels, T.
    Fox, B. D.
    Franckowiak, A.
    Franke, R.
    Gaisser, T. K.
    Gallagher, J.
    Gerhardt, L.
    Gladstone, L.
    Gluesenkamp, T.
    Goldschmidt, A.
    Goodman, J. A.
    Gora, D.
    Grant, D.
    Griesel, T.
    Gross, A.
    Grullon, S.
    Gurtner, M.
    Ha, C.
    Ismail, A. Haj
    Hallgren, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Halzen, F.
    Han, K.
    Hanson, K.
    Heinen, D.
    Helbing, K.
    Hellauer, R.
    Herquet, P.
    Hickford, S.
    Hill, G. C.
    Hoffman, K. D.
    Hoffmann, B.
    Homeier, A.
    Hoshina, K.
    Huelsnitz, W.
    Huelss, J. -P
    Hulth, P. O.
    Hultqvist, K.
    Hussain, S.
    Ishihara, A.
    Jacobi, E.
    Jacobsen, J.
    Japaridze, G. S.
    Johansson, H.
    Kampert, K. -H
    Kappes, A.
    Karg, T.
    Karle, A.
    Kenny, P.
    Kiryluk, J.
    Kislat, F.
    Klein, S. R.
    Koehne, J. -H
    Kohnen, G.
    Kolanoski, H.
    Koepke, L.
    Kopper, S.
    Koskinen, D. J.
    Kowalski, M.
    Kowarik, T.
    Krasberg, M.
    Kroll, G.
    Kurahashi, N.
    Kuwabara, T.
    Labare, M.
    Laihem, K.
    Landsman, H.
    Larson, M. J.
    Lauer, R.
    Luenemann, J.
    Madsen, J.
    Marotta, A.
    Maruyama, R.
    Mase, K.
    Matis, H. S.
    Meagher, K.
    Merck, M.
    Meszaros, P.
    Meures, T.
    Miarecki, S.
    Middell, E.
    Milke, N.
    Miller, J.
    Montaruli, T.
    Morse, R.
    Movit, S. M.
    Nahnhauer, R.
    Nam, J. W.
    Naumann, U.
    Nygren, D. R.
    Odrowski, S.
    Olivas, A.
    Olivo, M.
    O'Murchadha, A.
    Panknin, S.
    Paul, L.
    Pérez de los Heros, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Petrovic, J.
    Piegsa, A.
    Pieloth, D.
    Porrata, R.
    Posselt, J.
    Price, P. B.
    Przybylski, G. T.
    Rawlins, K.
    Redl, P.
    Resconi, E.
    Rhode, W.
    Ribordy, M.
    Richman, M.
    Rodrigues, J. P.
    Rothmaier, F.
    Rott, C.
    Ruhe, T.
    Rutledge, D.
    Ruzybayev, B.
    Ryckbosch, D.
    Sander, H. -G
    Santander, M.
    Sarkar, S.
    Schatto, K.
    Schmidt, T.
    Schoenwald, A.
    Schukraft, A.
    Schultes, A.
    Schulz, O.
    Schunck, M.
    Seckel, D.
    Semburg, B.
    Seo, S. H.
    Sestayo, Y.
    Seunarine, S.
    Silvestri, A.
    Spiczak, G. M.
    Spiering, C.
    Stamatikos, M.
    Stanev, T.
    Stezelberger, T.
    Stokstad, R. G.
    Stoessl, A.
    Strahler, E. A.
    Ström, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Stueer, M.
    Sullivan, G. W.
    Swillens, Q.
    Taavola, Henric
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Taboada, I.
    Tamburro, A.
    Ter-Antonyan, S.
    Tilav, S.
    Toale, P. A.
    Toscano, S.
    Tosi, D.
    van Eijndhoven, N.
    Vandenbroucke, J.
    Van Overloop, A.
    van Santen, J.
    Vehring, M.
    Voge, M.
    Walck, C.
    Waldenmaier, T.
    Wallraff, M.
    Walter, M.
    Weaver, Ch.
    Wendt, C.
    Westerhoff, S.
    Whitehorn, N.
    Wiebe, K.
    Wiebusch, C. H.
    Williams, D. R.
    Wischnewski, R.
    Wissing, H.
    Wolf, M.
    Wood, T. R.
    Woschnagg, K.
    Xu, C.
    Xu, D. L.
    Xu, X. W.
    Yanez, J. P.
    Yodh, G.
    Yoshida, S.
    Zarzhitsky, P.
    Zoll, M.
    Akerlof, C. W.
    Pandey, S. B.
    Yuan, F.
    Zheng, W.
    Searching for soft relativistic jets in core-collapse supernovae with the IceCube optical follow-up program2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 539, p. A60-Article in journal (Refereed)
    Abstract [en]

    Context. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of less than or similar to 100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 x 1051 erg, respectively, does not exceed 4.2% at 90% confidence.

  • 4. Abbasi, R.
    et al.
    Abdou, Y.
    Abu-Zayyad, T.
    Adams, J.
    Aguilar, J. A.
    Ahlers, M.
    Andeen, K.
    Auffenberg, J.
    Bai, X.
    Baker, M.
    Barwick, S. W.
    Bay, R.
    Alba, J. L. Bazo
    Beattie, K.
    Beatty, J. J.
    Bechet, S.
    Becker, J. K.
    Becker, K. -H
    Benabderrahmane, M. L.
    BenZvi, S.
    Berdermann, J.
    Berghaus, P.
    Berley, D.
    Bernardini, E.
    Bertrand, D.
    Besson, D. Z.
    Bissok, M.
    Blaufuss, E.
    Blumenthal, J.
    Boersma, D. J.
    Bohm, C.
    Bose, D.
    Boeser, S.
    Botner, Olga
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Braun, J.
    Buitink, S.
    Carson, M.
    Chirkin, D.
    Christy, B.
    Clem, J.
    Clevermann, F.
    Cohen, S.
    Colnard, C.
    Cowen, D. F.
    D'Agostino, M. V.
    Danninger, M.
    Davis, J. C.
    De Clercq, C.
    Demiroers, L.
    Depaepe, O.
    Descamps, F.
    Desiati, P.
    de Vries-Uiterweerd, G.
    DeYoung, T.
    Diaz-Velez, J. C.
    Dierckxsens, M.
    Dreyer, J.
    Dumm, J. P.
    Duvoort, M. R.
    Ehrlich, R.
    Eisch, J.
    Ellsworth, R. W.
    Engdegård, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Euler, S.
    Evenson, P. A.
    Fadiran, O.
    Fazely, A. R.
    Fedynitch, A.
    Feusels, T.
    Filimonov, K.
    Finley, C.
    Foerster, M. M.
    Fox, B. D.
    Franckowiak, A.
    Franke, R.
    Gaisser, T. K.
    Gallagher, J.
    Geisler, M.
    Gerhardt, L.
    Gladstone, L.
    Gluesenkamp, T.
    Goldschmidt, A.
    Goodman, J. A.
    Grant, D.
    Griesel, T.
    Gross, A.
    Grullon, S.
    Gurtner, M.
    Ha, C.
    Hallgren, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Halzen, F.
    Han, K.
    Hanson, K.
    Helbing, K.
    Herquet, P.
    Hickford, S.
    Hill, G. C.
    Hoffman, K. D.
    Homeier, A.
    Hoshina, K.
    Hubert, D.
    Huelsnitz, W.
    Huelss, J. -P
    Hulth, P. O.
    Hultqvist, K.
    Hussain, S.
    Ishihara, A.
    Jacobsen, J.
    Japaridze, G. S.
    Johansson, H.
    Joseph, J. M.
    Kampert, K. H.
    Kappes, A.
    Karg, T.
    Karle, A.
    Kelley, J. L.
    Kemming, N.
    Kenny, P.
    Kiryluk, J.
    Kislat, F.
    Klein, S. R.
    Koehne, J. -H
    Kohnen, G.
    Kolanoski, H.
    Koepke, L.
    Koskinen, D. J.
    Kowalski, M.
    Kowarik, T.
    Krasberg, M.
    Krings, T.
    Kroll, G.
    Kuehn, K.
    Kuwabara, T.
    Labare, M.
    Lafebre, S.
    Laihem, K.
    Landsman, H.
    Larson, M. J.
    Lauer, R.
    Lehmann, R.
    Luenemann, J.
    Madsen, J.
    Majumdar, P.
    Marotta, A.
    Maruyama, R.
    Mase, K.
    Matis, H. S.
    Matusik, M.
    Meagher, K.
    Merck, M.
    Meszaros, P.
    Meures, T.
    Middell, E.
    Milke, N.
    Miller, Jonathan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Montaruli, T.
    Morse, R.
    Movit, S. M.
    Nahnhauer, R.
    Nam, J. W.
    Naumann, U.
    Niessen, P.
    Nygren, D. R.
    Odrowski, S.
    Olivas, A.
    Olivo, M.
    O'Murchadha, A.
    Ono, M.
    Panknin, S.
    Paul, L.
    de los Heros, Carlos Perez
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Petrovic, J.
    Piegsa, A.
    Pieloth, D.
    Porrata, R.
    Posselt, J.
    Price, P. B.
    Prikockis, M.
    Przybylski, G. T.
    Rawlins, K.
    Redl, P.
    Resconi, E.
    Rhode, W.
    Ribordy, M.
    Rizzo, A.
    Rodrigues, J. P.
    Roth, P.
    Rothmaier, F.
    Rott, C.
    Ruhe, T.
    Rutledge, D.
    Ruzybayev, B.
    Ryckbosch, D.
    Sander, H. -G
    Santander, M.
    Sarkar, S.
    Schatto, K.
    Schlenstedt, S.
    Schmidt, T.
    Schukraft, A.
    Schultes, A.
    Schulz, O.
    Schunck, M.
    Seckel, D.
    Semburg, B.
    Seo, S. H.
    Sestayo, Y.
    Seunarine, S.
    Silvestri, A.
    Singh, K.
    Slipak, A.
    Spiczak, G. M.
    Spiering, C.
    Stamatikos, M.
    Stanev, T.
    Stephens, G.
    Stezelberger, T.
    Stokstad, R. G.
    Stoyanov, S.
    Strahler, E. A.
    Straszheim, T.
    Sullivan, G. W.
    Swillens, Q.
    Taavola, Henric
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Taboada, I.
    Tamburro, A.
    Tarasova, O.
    Tepe, A.
    Ter-Antonyan, S.
    Tilav, S.
    Toale, P. A.
    Toscano, S.
    Tosi, D.
    Turcan, D.
    van Eijndhoven, N.
    Vandenbroucke, J.
    Van Overloop, A.
    van Santen, J.
    Voge, M.
    Voigt, B.
    Walck, C.
    Waldenmaier, T.
    Wallraff, M.
    Walter, M.
    Weaver, Ch.
    Wendt, C.
    Westerhoff, S.
    Whitehorn, N.
    Wiebe, K.
    Wiebusch, C. H.
    Wikstroem, G.
    Williams, D. R.
    Wischnewski, R.
    Wissing, H.
    Wolf, M.
    Woschnagg, K.
    Xu, C.
    Xu, X. W.
    Yodh, G.
    Yoshida, S.
    Zarzhitsky, P.
    Constraints on high-energy neutrino emission from SN 2008D2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 527, no 4, p. A28-Article in journal (Refereed)
    Abstract [en]

    SN 2008D, a core collapse supernova at a distance of 27 Mpc, was serendipitously discovered by the Swift satellite through an associated X-ray flash. Core collapse supernovae have been observed in association with long gamma-ray bursts and X-ray flashes and a physical connection is widely assumed. This connection could imply that some core collapse supernovae possess mildly relativistic jets in which high-energy neutrinos are produced through proton-proton collisions. The predicted neutrino spectra would be detectable by Cherenkov neutrino detectors like IceCube. A search for a neutrino signal in temporal and spatial correlation with the observed X-ray flash of SN 2008D was conducted using data taken in 2007-2008 with 22 strings of the IceCube detector. Events were selected based on a boosted decision tree classifier trained with simulated signal and experimental background data. The classifier was optimized to the position and a "soft jet" neutrino spectrum assumed for SN 2008D. Using three search windows placed around the X-ray peak, emission time scales from 100-10 000 s were probed. No events passing the cuts were observed in agreement with the signal expectation of 0.13 events. Upper limits on the muon neutrino flux from core collapse supernovae were derived for different emission time scales and the principal model parameters were constrained. While no meaningful limits can be given in the case of an isotropic neutrino emission, the parameter space for a jetted emission can be constrained. Future analyses with the full 86 string IceCube detector could detect up to similar to 100 events for a core-collapse supernova at 10 Mpc according to the soft jet model.

  • 5. Abia, C.
    et al.
    de laverny, P.
    Wahlin, Rurik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    Chemical analysis of carbon stars in the Local Group2008In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 481, no 1, p. 161-168Article in journal (Refereed)
    Abstract [en]

    Aims. We present new results of our ongoing chemical study of carbon stars in Local Group galaxies to test the critical dependence of s-process nucleosynthesis on the stellar metallicity. Methods. We collected optical spectra with the VLT/UVES instrument of two carbon stars found in the Carina Dwarf Spheroidal (dSph) galaxy, namely ALW-C6 and ALW-C7. We performed a full chemical analysis using the new generation of hydrostatic, spherically symmetric carbon-rich model atmospheres and the spectral synthesis method in LTE. Results. The luminosities, atmosphere parameters and chemical composition of ALW-C6 and ALW-C7 are compatible with these stars being in the TP-AGB phase undergoing third dredge-up episodes, although their extrinsic nature ( external pollution in a binary stellar system) cannot be definitively excluded. Our chemical analysis shows that the metallicity of both stars agree with the average metallicity ([Fe/H] similar to -1.8 dex) previously derived for this satellite galaxy from the analysis of both low resolution spectra of RGB stars and the observed colour magnitude diagrams. ALW-C6 and ALW-C7 present strong s-element enhancements, [s/Fe] = + 1.6, + 1.5, respectively. These enhancements and the derived s-process indexes [ls/Fe], [hs/Fe] and [hs/ls] are compatible with theoretical s-process nucleosynthesis predictions in low mass AGB stars (similar to 1.5 M(circle dot)) on the basis that the (13)C(alpha, n) (16)O is the main source of neutrons. Furthermore, the analysis of C(2) and CN bands reveals a large carbon enhancement (C/O similar to 7 and 5, respectively), much larger than the values typically found in galactic AGB carbon stars ( C/O similar to 1-2). This is also in agreement with the theoretical prediction that AGB carbon stars are formed more easily through third dredge-up episodes as the initial stellar metallicity drops. However, theoretical low-mass AGB models apparently fail to simultaneously fit the observed s-element and carbon enhancements. On the other hand, Zr is found to be less enhanced in ALW-C7 compared to the other elements belonging to the same s-peak. Although the abundance errors are large, the fact that in this star the abundance of Ti ( which has a similar condensation temperature to Zr) seems also to be lower than those of others metals, may indicate the existence of some depletion into dust-grains in its photosphere.

  • 6. Adén, D.
    et al.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Feltzing, S.
    Grebel, E. K.
    Koch, A.
    Wilkinson, M. I.
    An abundance study of red-giant-branch stars in the Hercules dwarf spheroidal galaxy2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 525, p. A153-Article in journal (Refereed)
    Abstract [en]

    Context. Dwarf spheroidal galaxies are some of the most metal-poor, and least luminous objects known. Detailed elemental abundance analysis of stars in these faint objects is key to our understanding of star formation and chemical enrichment in the early universe, and may provide useful information on how larger galaxies form. Aims. Our aim is to provide a determination of [Fe/H] and [Ca/H] for confirmed red-giant branch member stars of the Hercules dwarf spheroidal galaxy. Based on this we explore the ages of the prevailing stellar populations in Hercules, and the enrichment history from supernovae. Additionally, we aim to provide a new simple metallicity calibration for Stromgren photometry for metal-poor, red giant branch stars. Methods. High-resolution, multi-fibre spectroscopy and Stromgren photometry are combined to provide as much information on the stars as possible. From this we derive abundances by solving the radiative transfer equations through marcs model atmospheres. Results. We find that the red-giant branch stars of the Hercules dSph galaxy are more metal-poor than estimated in our previous study that was based on photometry alone. From this, we derive a new metallicity calibration for the Stromgren photometry. Additionally, we find an abundance trend such that [Ca/Fe] is higher for more metal-poor stars, and lower for more metal-rich stars, with a spread of about 0.8 dex. The [Ca/Fe] trend suggests an early rapid chemical enrichment through supernovae of type II, followed by a phase of slow star formation dominated by enrichment through supernovae of type Ia. A comparison with isochrones indicates that the red giants in Hercules are older than 10 Gyr.

  • 7. Alecian, E.
    et al.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Neiner, C.
    Wade, G. A.
    de Batz, B.
    Henrichs, H.
    Grunhut, J. H.
    Bouret, J. -C
    Briquet, M.
    Gagne, M.
    Naze, Y.
    Oksala, M. E.
    Rivinius, T.
    Townsend, R. H. D.
    Walborn, N. R.
    Weiss, W.
    First HARPSpol discoveries of magnetic fields in massive stars2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 536, p. L6-Article in journal (Refereed)
    Abstract [en]

    In the framework of the Magnetism in Massive Stars (MiMeS) project, a HARPSpol Large Program at the 3.6m-ESO telescope has recently started to collect high-resolution spectropolarimetric data of a large number of Southern massive OB stars in the field of the Galaxy and in many young clusters and associations. We report on the first discoveries of magnetic fields in two massive stars with HARPSpol - HD 130807 and HD 122451, and confirm the presence of a magnetic field at the surface of HD 105382 that was previously observed with a low spectral resolution device. The longitudinal magnetic field measurements strongly vary for HD 130807 from similar to-100 G to similar to 700 G. Those of HD 122451 and HD 105382 are less variable with values ranging from similar to-40 to -80 G, and from similar to-300 to -600 G, respectively. The discovery and confirmation of three new magnetic massive stars, including at least two He-weak stars, is an important contribution to one of MiMeS objectives: the understanding of the origin of magnetic fields in massive stars and their impact on stellar structure and evolution.

  • 8. Alecian, E.
    et al.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Petit, V.
    Grunhut, J.
    Landstreet, J.
    Oksala, M. E.
    Wade, G. A.
    Hussain, G.
    Neiner, C.
    Bohlender, D.
    Discovery of new magnetic early-B stars within the MiMeS HARPSpol survey2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 567, p. A28-Article in journal (Refereed)
    Abstract [en]

    Context. The Magnetism in Massive Stars (MiMeS) project aims at understanding the origin of the magnetic fields in massive stars as well as their impact on stellar internal structure, evolution, and circumstellar environment. Aims. One of the objectives of the MiMeS project is to provide stringent observational constraints on the magnetic fields of massive stars; however, identification of magnetic massive stars is challenging, as only a few percent of high-mass stars host strong fields detectable with the current instrumentation. Hence, one of the first objectives of the MiMeS project was to search for magnetic objects among a large sample of massive stars, and to build a sub-sample for in-depth follow-up studies required to test the models and theories of fossil field origins, magnetic wind confinement and magnetospheric properties, and magnetic star evolution. Methods. We obtained high-resolution spectropolarimetric observations of a large number of OB stars thanks to three large programs (LP) of observations that have been allocated on the high-resolution spectropolarimeters ESPaDOnS, Narval, and the polarimetric module HARPSpol of the HARPS spectrograph. We report here on the methods and first analysis of the HARPSpol magnetic detections. We identified the magnetic stars using a multi-line analysis technique. Then, when possible, we monitored the new discoveries to derive their rotation periods, which are critical for follow-up and magnetic mapping studies. We also performed a first-look analysis of their spectra and identified obvious spectral anomalies (e. g., surface abundance peculiarities, Ha emission), which are also of interest for future studies. Results. In this paper, we focus on eight of the 11 stars in which we discovered or confirmed a magnetic field from the HARPSpol LP sample (the remaining three were published in a previous paper). Seven of the fields were detected in early-type Bp stars, while the last field was detected in the Ap companion of a normal early B-type star. We report obvious spectral and multiplicity properties, as well as our measurements of their longitudinal field strengths, and their rotation periods when we are able to derive them. We also discuss the presence or absence of Ha emission with respect to the theory of centrifugally-supported magnetospheres.

  • 9. Alecian, E.
    et al.
    Neiner, C.
    Mathis, S.
    Catala, C.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Landstreet, J.
    The dramatic change of the fossil magnetic field of HD 190073: Evidence of the birth of the convective core in a Herbig star?2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 549, p. L8-Article in journal (Refereed)
    Abstract [en]

    In the context of the ESPaDOnS and Narval spectropolarimetric surveys of Herbig Ae/Be stars, we discovered and then monitored the magnetic field of HD 190073 over more than four years, from 2004 to 2009. Our observations all displayed similar Zeeman signatures in the Stokes V spectra, indicating that HD 190073 hosted an aligned dipole, stable over many years, consistent with a fossil origin. We obtained new observations of the star in 2011 and 2012 and detected clear variations of the Zeeman signature on timescales of days to weeks, indicating that the configuration of its field has changed between 2009 and 2011. Such a sudden change of external structure of a fossil field has never previously been observed in any intermediate or high-mass star. HD 190073 is an almost entirely radiative pre-main sequence star, probably hosting a growing convective core. We propose that this dramatic change is the result of the interaction between the fossil field and the ignition of a dynamo field generated in the newly-born convective core.

  • 10.
    Alvarado-Gomez, J. D.
    et al.
    European So Observ, D-85748 Garching, Germany.;Univ Munich, Univ Sternwarte Munchen, D-81679 Munich, Germany..
    Hussain, G. A. J.
    European So Observ, D-85748 Garching, Germany.;Univ Toulouse, UPS OMP, Inst Rech Astrophys & Planetol, F-31400 Toulouse, France..
    Grunhut, J.
    European So Observ, D-85748 Garching, Germany..
    Fares, R.
    INAF Osservatorio Astrofis Catania, I-95123 Catania, Italy..
    Donati, J. -F
    Alecian, E.
    UJF Grenoble 1, CNRS, INSU, IPAG,UMR 5274, Grenoble, France.;Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris,UMR 8109, F-92190 Meudon, France..
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Oksala, M.
    Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris,UMR 8109, F-92190 Meudon, France..
    Morin, J.
    CNRS, UMR 5299, LUPM, F-34095 Montpellier 05, France.;Univ Montpellier, F-34095 Montpellier 05, France..
    Redfield, S.
    Wesleyan Univ, Dept Astron, Van Vleck Observ, Middletown, CT 06459 USA..
    Cohen, O.
    Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA..
    Drake, J. J.
    Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA..
    Jardine, M.
    Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland..
    Matt, S.
    Univ Exeter, Dept Phys & Astron, Exeter EX4 4SB, Devon, England..
    Petit, P.
    Univ Toulouse, UPS OMP, Inst Rech Astrophys & Planetol, F-31400 Toulouse, France.;CNRS, Inst Rech Astrophys & Planetol, F-31400 Toulouse, France..
    Walter, F. M.
    SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA..
    Activity and magnetic field structure of the Sun-like planet-hosting star HD 12372015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 582, article id A38Article in journal (Refereed)
    Abstract [en]

    We analyse the magnetic activity characteristics of the planet-hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field measurements that is consistent with our ZDI analysis with a period of 7 days. We investigate the effect of customising the LSD mask to the line depths of the observed spectrum and find that it has a minimal effect on the shape of the extracted Stokes V profile but does result in a small increase in the S/N (similar to 7%). We find that using a Milne-Eddington solution to describe the local line profile provides a better fit to the LSD profiles in this slowly rotating star, which also affects the recovered ZDI field distribution. We also introduce a fit-stopping criterion based on the information content (entropy) of the ZDI map solution set. The recovered magnetic field maps show a strong (+90 G) ring-like azimuthal field distribution and a complex radial field dominating at mid latitudes (similar to 45 degrees). Similar magnetic field maps are recovered from data acquired five months apart. Future work will investigate how this surface magnetic field distribution affeccts the coronal magnetic field and extended environment around this planet-hosting star.

  • 11.
    Amarsi, A. M.
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Collet, R.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
    Zatsarinny, O.
    Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA.
    Inelastic O plus H collisions and the O I 777 nm solar centre-to-limb variation2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A89Article in journal (Refereed)
    Abstract [en]

    The O I 777 nm triplet is a key diagnostic of oxygen abundances in the atmospheres of FGK-type stars; however, it is sensitive to departures from local thermodynamic equilibrium (LTE). The accuracy of non-LTE line formation calculations has hitherto been limited by errors in the inelastic O+H collisional rate coefficients; several recent studies have used the Drawin recipe, albeit with a correction factor S-H that is calibrated to the solar centre-to-limb variation of the triplet. We present a new model oxygen atom that incorporates inelastic O+H collisional rate coefficients using an asymptotic two-electron model based on linear combinations of atomic orbitals, combined with a free electron model based on the impulse approximation. Using a 3D hydrodynamic STAGGER model solar atmosphere and 3D non-LTE line formation calculations, we demonstrate that this physically motivated approach is able to reproduce the solar centre-to-limb variation of the triplet to 0.02 dex, without any calibration of the inelastic collisional rate coefficients or other free parameters. We infer log epsilon(O) = 8.69 +/- 0.03 from the triplet alone, strengthening the case for a low solar oxygen abundance.

  • 12.
    Amarsi, A. M.
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Nordlander, T.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia;ARC Ctr Excellence All Sky Astrophys 3 Dimens AST, Canberra, ACT, Australia.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Collet, R.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Effective temperature determinations of late-type stars based on 3D non-LTE Balmer line formation2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 615, article id A139Article in journal (Refereed)
    Abstract [en]

    Hydrogen Balmer lines are commonly used as spectroscopic effective temperature diagnostics of late-type stars. However, reliable inferences require accurate model spectra, and the absolute accuracy of classical methods that are based on one-dimensional (1D) hydrostatic model atmospheres and local thermodynamic equilibrium (LTE) is still unclear. To investigate this, we carry out 3D non-LTE calculations for the Balmer lines, performed, for the first time, over an extensive grid of 3D hydrodynamic STAGGER model atmospheres. For H alpha, H beta, and H gamma we find significant 1D non-LTE versus 3D non-LTE differences (3D effects): the outer wings tend to be stronger in 3D models, particularly for H gamma, while the inner wings can be weaker in 3D models, particularly for H alpha. For H alpha, we also find significant 3D LTE versus 3D non-LTE differences (non-LTE effects): in warmer stars (T-eff approximate to 6500 K) the inner wings tend to be weaker in non-LTE models, while at lower effective temperatures (T-eff approximate to 4500 K) the inner wings can be stronger in non-LTE models; the non-LTE effects are more severe at lower metallicities. We test our 3D non-LTE models against observations of well-studied benchmark stars. For the Sun, we infer concordant effective temperatures from H alpha, H beta, and H gamma; however the value is too low by around 50 K which could signal residual modelling shortcomings. For other benchmark stars, our 3D non-LTE models generally reproduce the effective temperatures to within 1 sigma uncertainties. For H alpha, the absolute 3D effects and non-LTE effects can separately reach around 100 K, in terms of inferred effective temperatures. For metal-poor turn-off stars, 1D LTE models of H alpha can underestimate effective temperatures by around 150 K. Our 3D non-LTE model spectra are publicly available, and can be used for more reliable spectroscopic effective temperature determinations.

  • 13.
    Andrae, Rene
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Fouesneau, Morgan
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Creevey, Orlagh
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Ordenovic, Christophe
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Mary, Nicolas
    Thales Serv, 290 Allee Lac, F-31670 Labege, France.
    Burlacu, Alexandru
    Telespazio France, 26 Ave Jean Francois Champollion, F-31100 Toulouse, France.
    Chaoul, Laurence
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Jean-Antoine-Piccolo, Anne
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Kordopatis, Georges
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Lebreton, Yveline
    Univ Rennes 1, Inst Phys Rennes, CNRS, UMR 6251, F-35042 Rennes, France;Univ Paris Diderot, LESIA, Observ Paris, PSL Res Univ,CNRS,UMR 8109,Univ Pierre & Marie Cu, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Panem, Chantal
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Pichon, Bernard
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Thevenin, Frederic
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Walmsley, Gavin
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Bailer-Jones, Coryn A. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    First stellar parameters from Apsis2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A8Article in journal (Refereed)
    Abstract [en]

    The second Gaia data release (Gaia DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. One band is the G band, the other two were obtained by integrating the Gaia prism spectra (BP and RP). We have used these three broad photometric bands to infer stellar effective temperatures, T-eff, for all sources brighter than G = 17 mag with T-eff in the range 3000-10 000K (some 161 million sources). Using in addition the parallaxes, we infer the line-of-sight extinction, A(G), and the reddening, E(BP-RP), for 88 million sources. Together with a bolometric correction we derive luminosity and radius for 77 million sources. These quantities as well as their estimated uncertainties are part of Gaia DR2. Here we describe the procedures by which these quantities were obtained, including the underlying assumptions, comparison with literature estimates, and the limitations of our results. Typical accuracies are of order 324K (T-eff), 0.46 mag (A(G)), 0.23 mag (E(BP-RP)), 15% (luminosity), and 10% (radius). Being based on only a small number of observable quantities and limited training data, our results are necessarily subject to some extreme assumptions that can lead to strong systematics in some cases (not included in the aforementioned accuracy estimates). One aspect is the non-negativity contraint of our estimates, in particular extinction, which we discuss. Yet in several regions of parameter space our results show very good performance, for example for red clump stars and solar analogues. Large uncertainties render the extinctions less useful at the individual star level, but they show good performance for ensemble estimates. We identify regimes in which our parameters should and should not be used and we define a "clean" sample. Despite the limitations, this is the largest catalogue of uniformly-inferred stellar parameters to date. More precise and detailed astrophysical parameters based on the full BP/RP spectrophotometry are planned as part of the third Gaia data release.

  • 14.
    Aronson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Bladh, S.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Modelling polarized light from dust shells surrounding asymptotic giant branch stars2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 603, article id A116Article in journal (Refereed)
    Abstract [en]

    Context. Winds of asymptotic giant branch (AGB) stars are commonly assumed to be driven by radiative acceleration of dust grains. For M-type AGB stars, the nature of the wind-driving dust species has been a matter of intense debate. A proposed source of the radiation pressure triggering the outflows is photon scattering on Fe-free silicate grains. This wind-driving mechanism requires grain radii of about 0.1-1 micron in order to make the dust particles efficient at scattering radiation around the stellar flux maximum. Grain size is therefore an important parameter for understanding the physics behind the winds of M-type AGB stars. Aims. We seek to investigate the diagnostic potential of scattered polarized light for determining dust grain sizes. Methods. We have developed a new tool for computing synthetic images of scattered light in dust and gas shells around AGB stars, which can be applied to detailed models of dynamical atmospheres and dust-driven winds. Results. We present maps of polarized light using dynamical models computed with the DARWIN code. The synthetic images clearly show that the intensity of the polarized light, the position of the inner edge of the dust shell, and the size of the dust grains near the inner edge are all changing with the luminosity phase. Non-spherical structures in the dust shells can also have an impact on the polarized light. We simulate this effect by combining different pulsation phases into a single 3D structure before computing synthetic images. An asymmetry of the circumstellar envelope can create a net polarization, which can be used as diagnostics for the grain size. The ratio between the size of the scattering particles and the observed wavelength determines at what wavelengths net polarization switches direction. If observed, this can be used to constrain average particle sizes.

  • 15.
    Aronson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Waldén, P.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Piskunov, Nikolai
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Using near-infrared spectroscopy for characterization of transiting exoplanets2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 578, article id A133Article in journal (Refereed)
    Abstract [en]

    Context. We propose a method for observing transiting exoplanets with near-infrared high-resolution spectrometers. Aims. We aim to create a robust data analysis method for recovering atmospheric transmission spectra from transiting exoplanets over a wide wavelength range in the near-infrared. Methods. By using an inverse method approach, combined with stellar models and telluric transmission spectra, the method recovers the transiting exoplanet's atmospheric transmittance at high precision over a wide wavelength range. We describe our method and have tested it by simulating observations. Results. This method is capable of recovering transmission spectra of high enough accuracy to identify absorption features from molecules such as O-2, CH4, CO2, and H2O. This accuracy is achievable for Jupiter-size exoplanets at S/N that can be reached for 8m class telescopes using high-resolution spectrometers (R > 20 000) during a single transit, and for Earth-size planets and super-Earths transiting late K or M dwarf stars at S/N reachable during observations of less than 10 transits. We also analyse potential error sources to show the robustness of the method. Conclusions. Detection and characterization of atmospheres of both Jupiter-size planets and smaller rocky planets looks promising using this set-up.

  • 16. Arroyo-Torres, B.
    et al.
    Wittkowski, M.
    Chiavassa, A.
    Scholz, M.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Marcaide, J. M.
    Hauschildt, P. H.
    Wood, P. R.
    Abellan, F. J.
    What causes the large extensions of red supergiant atmospheres?: Comparisons of interferometric observations with 1D hydrostatic, 3D convection, and 1D pulsating model atmospheres2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 575, article id A50Article in journal (Refereed)
    Abstract [en]

    Aims. This research has two main goals. First, we present the atmospheric structure and the fundamental parameters of three red supergiants (RSGs), increasing the sample of RSGs observed by near-infrared spectro-interferometry. Additionally, we test possible mechanisms that may explain the large observed atmospheric extensions of RSGs. Methods. We carried out spectro-interferometric observations of the.RSGs V602 Car, EID 95687, and EID 183589 in the near-infrared K-band (1.92-2.47 mu m) with the VLTI/AMBER instrument at medium spectral resolution (R similar to 1500). To categorize and comprehend the extended atmospheres, we compared our observational results to predictions by available hydrostatic PHOENIX, available 3D convection, and new 1D self-excited pulsation models of RSGs. Results. Our near-infrared flux spectra of V602 Car, HD 95687, and HD 183589 are well reproduced by the PHOENIX model atmospheres. The continuum visibility values are consistent with a limb-darkened disk as predicted by the PHOENIX models, allowing us to determine the angular diameter and the fundamental parameters of our sources. Nonetheless, in the case of V602 Car and HD 95686, the PHOENIX model visibilities do not predict the large observed extensions of molecular layers, most remarkably in the CO bands. Likewise, the 3D convection models and the ID pulsation models with typical parameters of RSGs lead to compact atmospheric structures as well, which are similar to the structure of the hydrostatic PHOENIX models. They can also not explain the observed decreases in the visibilities and thus the large atmospheric molecular extensions. The full sample of our RSGs indicates increasing observed atmospheric extensions with increasing luminosity and decreasing surface gravity, and no correlation with effective temperature or variability amplitude. Conclusions. The location of our RSG sources in the Hertzsprung-Russell diagram is contirm.ed to be consistent with the red limits of recent evolutionary tracks. The observed extensions of the atmospheric layers of our sample of RSGs are comparable to those of Mira stars. This phenomenon is not predicted by any of the considered model atmospheres including as 311) convection and new 1D pulsation models of.RSGs. This confirms that neither convection nor pulsation alone can levitate the molecular atmospheres of.RSGs. Our observed correlation of atmospheric extension with luminosity supports a scenario of radiative acceleration on Doppler-shifted molecular lines.

  • 17.
    Attree, N.
    et al.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Nebouy, D.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Thomas, N.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Brouet, Y.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Kuehrt, E.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Preusker, F.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Scholten, F.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Knollenberg, J.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Hartogh, P.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Rodrigo, R.
    INTA CSIC, Ctr Astrobiol, Madrid 28691, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Koschny, D.
    ESA, Sci Support Off, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Bartycka 18A, PL-00716 Warsaw, Poland..
    Keller, H. U.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany.;TU Braunschweig, Inst Geophys & Extraterrestrial Phys, D-38106 Braunschweig, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Auger, A. -T
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Obs Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Bodewits, D.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Cremonese, G.
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B.
    Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Debei, S.
    Univ Padua, Dept Ind Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, UNITN, Via Mesiano 77, I-38100 Trento, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    El-Maarry, M. R.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Obs Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Fulle, M.
    INAF Osservatorio Astronom, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Ip, W. -H
    Kovacs, G.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kramm, J. R.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kueppers, M.
    ESA, European Space Astron Ctr, Operat Dept, POB 78, Madrid 28691, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Lazzarin, M.
    Moreno, J. J. Lopez
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Lowry, S.
    Univ Kent, Sch Phys Sci SEPnet, Ctr Astrophys & Planetary Sci, Canterbury CT2 7NH, Kent, England..
    Marchi, S.
    Southwest Res Inst, 1050 Walnut St, Boulder, CO 80302 USA..
    Marzari, F.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Mottola, S.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Naletto, G.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy.;Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy.;CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Oklay, N.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Pajola, M.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Toth, I.
    MTA CSFK Konkoly Observ, Konkoly Thege M Ut 15-17, H-1121 Budapest, Hungary..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Shi, X.
    Tensile strength of 67P/Churyumov-Gerasimenko nucleus material from overhangs2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 611, article id A33Article in journal (Refereed)
    Abstract [en]

    We directly measured twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimated the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around 1 Pa or less (1 to 5 Pa, when scaled to a metre length). The presence of eroded material at the base of most overhangs, as well as the observed collapse of two features and the implied previous collapse of another, suggests that they are prone to failure and that the true material strengths are close to these lower limits (although we only consider static stresses and not dynamic stress from, for example, cometary activity). Thus, a tensile strength of a few pascals is a good approximation for the tensile strength of the 67P nucleus material, which is in agreement with previous work. We find no particular trends in overhang properties either with size over the similar to 10-100 m range studied here or location on the nucleus. There are no obvious differences, in terms of strength, height or evidence of collapse, between the populations of overhangs on the two cometary lobes, suggesting that 67P is relatively homogenous in terms of tensile strength. Low material strengths are supportive of cometary formation as a primordial rubble pile or by collisional fragmentation of a small body (tens of km).

  • 18. Auger, A. -T
    et al.
    Groussin, O.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Jorda, L.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Bouley, S.
    Univ Paris 11, Lab GEOPS, Geosci Paris Sud, F-91405 Orsay, France.;Inst Mecan Celeste & Calcul Ephemerides, UMR 8028, F-75014 Paris, France..
    Gaskell, R.
    Planetary Sci Inst, Tucson, AZ 85719 USA..
    Lamy, P. L.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Capanna, C.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Thomas, N.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Pommerol, A.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Rodrigo, R.
    Ctr Astrobiol INTA CSIC, Madrid 28691, Spain.;Int Space Sci Inst, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Sci Support Off, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Keller, H. U.
    Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, Observ Paris, LESIA,CNRS, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, CISAS, I-35100 Padua, Italy..
    Cremonese, G.
    Univ Padua, Dept Mech Engn, I-35131 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Debei, S.
    Univ Padua, Dept Mech Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, UNITN, I-38100 Trento, Italy..
    El-Maarry, M. R.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, Observ Paris, LESIA,CNRS, F-92195 Meudon, France..
    Fulle, M.
    Osserv Astron Trieste, INAF, I-34143 Trieste, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Ip, W. -H
    Knollenberg, J.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kueppers, M.
    European Space Astron Ctr ESA, Operat Dept, Madrid 28691, Spain..
    La Forgia, F.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marchi, S.
    Southwest Res Inst, Boulder, CO 80302 USA..
    Marzari, F.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Massironi, M.
    Osserv Astron Padova, INAF, I-35121 Padua, Italy.;Univ Padua, Ctr Ateneo Studi & Attivita Spaziali Giuseppe Col, I-35131 Padua, Italy..
    Michalik, H.
    Tech Univ Carolo Wilhelmina Braunschweig, Inst Datentech & Kommunikat Netze, D-38106 Braunschweig, Germany..
    Naletto, G.
    Univ Padua, CISAS, I-35100 Padua, Italy.;CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Pajola, M.
    Univ Padua, Ctr Ateneo Studi & Attivita Spaziali Giuseppe Col, I-35131 Padua, Italy..
    Sabau, L.
    Inst Nacl Tecn Aeroesp, Madrid 28850, Spain..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Wenzel, K. -P
    Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 583, article id A35Article in journal (Refereed)
    Abstract [en]

    Context. Since August 2014, the OSIRIS Narrow Angle Camera (NAC) onboard the Rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko, down to the decimeter scale. This paper focuses on the Imhotep region, located on the largest lobe of the nucleus, near the equator. Aims. We map, inventory, and describe the geomorphology of the Imhotep region. We propose and discuss some processes to explain the formation and ongoing evolution of this region. Methods. We used OSIRIS NAC images, gravitational heights and slopes, and digital terrain models to map and measure the morphologies of Imhotep. Results. The Imhotep region presents a wide variety of terrains and morphologies: smooth and rocky terrains, bright areas, linear features, roundish features, and boulders. Gravity processes such as mass wasting and collapse play a significant role in the geomorphological evolution of this region. Cometary processes initiate erosion and are responsible for the formation of degassing conduits that are revealed by elevated roundish features on the surface. We also propose a scenario for the formation and evolution of the Imhotep region; this implies the presence of large primordial voids inside the nucleus, resulting from its formation process.

  • 19.
    Babusiaux, C.
    et al.
    Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    van Leeuwen, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Barstow, M. A.
    Univ Leicester, Dept Phys & Astron, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Jordi, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Vallenari, A.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bossini, D.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bressan, A.
    SISSA, Via Bonomea 265, I-34136 Trieste, Italy.
    Cantat-Gaudin, T.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    van Leeuwen, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Brown, A. G. A.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Prusti, T.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    de Bruijne, J. H. J.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Bailer-Jones, C. A. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Biermann, M.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Evans, D. W.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Eyer, L.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Jansen, F.
    ESA ESTEC, Directorate Sci, Operat Dept, Miss Operat Div, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Klioner, S. A.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Lammers, U.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Lindegren, L.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Luri, X.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Mignard, F.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Panem, C.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Pourbaix, D.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium;FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium.
    Randich, S.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Sartoretti, P.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Siddiqui, H. I.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Soubiran, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Walton, N. A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Arenou, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Bastian, U.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Cropper, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drimmel, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Katz, D.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lattanzi, M. G.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Bakker, J.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cacciari, C.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Castaneda, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Chaoul, L.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Cheek, N.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    De Angeli, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Fabricius, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Guerra, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Holl, B.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Masana, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Messineo, R.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Mowlavi, N.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Nienartowicz, K.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Panuzzo, P.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Portell, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Riello, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Seabroke, G. M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Tanga, P.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Thevenin, F.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Gracia-Abril, G.
    ESAC, Gaia DPAC Project Off, Camino Bajo Castillo S-N, Madrid 28692, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Comoretto, G.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Garcia-Reinaldos, M.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Teyssier, D.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Altmann, M.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Andrae, R.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Audard, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Bellas-Velidis, I.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Benson, K.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Berthier, J.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Blomme, R.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Burgess, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Busso, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Carry, B.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France;Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Cellino, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Clementini, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Clotet, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Creevey, O.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Davidson, M.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    De Ridder, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Delchambre, L.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Dell'Oro, A.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Ducourant, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Fernandez-Hernandez, J.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fouesneau, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Fremat, Y.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Galluccio, L.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Garcia-Torres, M.
    Univ Pablo Olavide, Area Lenguajes Sistemas Informat, Ctr Utrera,Km 1, Seville 41013, Spain.
    Gonzalez-Nunez, J.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain;Univ Vigo, ETSE Telecomun, Campus Lagoas Marcosende, Vigo 36310, Spain.
    Gonzalez-Vidal, J. J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Gosset, E.
    FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Guy, L. P.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Halbwachs, J. -L
    Hambly, N. C.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Harrison, D. L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Cambridge, Kavli Inst Cosmol, Madingley Rd, Cambride CB3 0HA, England.
    Hernandez, J.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Hestroffer, D.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Hodgkin, S. T.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Hutton, A.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Jasniewicz, G.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 05, France.
    Jean-Antoine-Piccolo, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Jordan, S.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Krone-Martins, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Lanzafame, A. C.
    Univ Catania, Dipartimento Fis & Astron, Sez Astrofis, Via S Sofia 78, I-95123 Catania, Italy;INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Lebzelter, T.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Loeffler, W.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Manteiga, M.
    Univ A Coruna, CITIC Astron & Astrophys, Campus Elvina S-N, La Coruna 15071, Spain;Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Marrese, P. M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Martin-Fleitas, J. M.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Moitinho, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Mora, A.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Muinonen, K.
    Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland;Finnish Geospatial Res Inst FGI, Geodeetinrinne 2, Masala 02430, Finland.
    Osinde, J.
    ESA ESAC, Isdefe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Pancino, E.
    ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy;INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Pauwels, T.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Petit, J. -M
    Recio-Blanco, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Richards, P. J.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Rimoldini, L.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Robin, A. C.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Sarro, L. M.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Siopis, C.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Smith, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Sozzetti, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Sueveges, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Torra, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    van Reeven, W.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Abbas, U.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Abreu Aramburu, A.
    ESA ESAC, Elecnor Deimos Space, Camino Bajo Castillo S-N, Madrid 28692, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Accart, S.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Aerts, C.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Altavilla, G.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Alvarez, M. A.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Alvarez, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Alves, J.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Anderson, R. I.
    European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Andrei, A. H.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France;ON MCTI BR, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, Brazil;OV UFRJ BR, Ladeira Pedro Antonio 43, BR-20080090 Rio De Janeiro, Brazil.
    Anglada Varela, E.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Antiche, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Antoja, T.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Arcay, B.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Astraatmadja, T. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Carnegie Inst Sci, Dept Terr Magnetism, 5241 Broad Branch Rd,NW, Washington, DC 20015 USA.
    Bach, N.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Baker, S. G.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Balaguer-Nunez, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Balm, P.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Barache, C.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Barata, C.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Barbato, D.
    Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Barblan, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Barrado, D.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Barros, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Bartholome Munoz, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bassilana, J. -L
    Becciani, U.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bellazzini, M.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Berihuete, A.
    Univ Cadiz, Dept Estadist, Calle Republica Arabe Saharawi S-N, Puerto Real 11510, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bertones, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Bern Univ, Astron Inst, Sidlerstr 5, CH-3012 Bern, Switzerland.
    Bianchi, L.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Bienayme, O.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Blanco-Cuaresma, S.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA;Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Boch, T.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Boeche, C.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bombrun, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Borrachero, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bouquillon, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Bourda, G.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bragaglia, A.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Bramante, L.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Breddels, M. A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Brouillet, N.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bruesemeister, T.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Brugaletta, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bucciarelli, B.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Burlacu, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Busonero, D.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Butkevich, A. G.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Buzzi, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Caffau, E.
    Cancelliere, R.
    Univ Turin, Dept Comp Sci, Corso Svizzera 185, I-10149 Turin, Italy.
    Cannizzaro, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Carballo, R.
    Univ Cantabria, Dept Matemat Aplicada & Ciencias Comp, ETS Ingenieros Caminos Canales & Puertos, Avda Castros S-N, E-39005 Santander, Spain.
    Carlucci, T.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Carrasco, J. M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Casamiquela, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Castellani, M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy.
    Castro-Ginard, A.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Charlot, P.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Chemin, L.
    Univ Antofagasta, Unidad Astron, Ave Angamos 601, Antofagasta 1270300, Chile.
    Chiavassa, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Cocozza, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Costigan, G.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Cowell, S.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Crifo, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Crosta, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Crowley, C.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cuypers, J.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Dafonte, C.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Damerdji, Y.
    CRAAG, Route Observ Bp 63, Algiers 16340, Algeria;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Dapergolas, A.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    David, P.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    David, M.
    Univ Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, B-2020 Antwerp, Belgium.
    de laverny, P.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    De Luise, F.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    De March, R.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    de Martino, D.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    de Souza, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    de Torres, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Debosscher, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    del Pozo, E.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Delbo, M.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Delgado, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Delgado, H. E.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Diakite, S.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Diener, C.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Distefano, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Dolding, C.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drazinos, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Duran, J.
    ESA ESAC, Isdefe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Edvardsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Enke, H.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Esquej, P.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Bontemps, G. Eynard
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabre, C.
    CNES Ctr Spatial Toulouse, ATOS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabrizio, M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Faigler, S.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Falcao, A. J.
    UNINOVA CTS, Campus FCT UNL, P-2829516 Caparica, Portugal.
    Casas, M. Farras
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Federici, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Fedorets, G.
    Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Fernique, P.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Figueras, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Filippi, F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Findeisen, K.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Fonti, A.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Fraile, E.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fraser, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Coll Dublin, Sch Phys, OBrien Ctr Sci North, Dublin 4, Ireland.
    Frezouls, B.
    Univ Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, B-2020 Antwerp, Belgium.
    Gai, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Galleti, S.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garabato, D.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Garcia-Sedano, F.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Garofalo, A.
    Univ Bologna, Dipartimento Fis & Astron, Via Piero Gobetti 93-2, I-40129 Bologna, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garralda, N.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Gavel, Alvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Gavras, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Gerssen, J.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Geyer, R.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Giacobbe, P.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Gilmore, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Girona, S.
    Ctr Nacl Super Comp, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus 2, Barcelona 08034, Spain.
    Giuffrida, G.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Glass, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Gomes, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Granvik, M.
    Lulea Univ Technol, Dept Comp Sci Elect & Space Engn, Box 848, S-98128 Kiruna, Sweden;Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Gueguen, A.
    Max Planck Inst Extraterrestrial Phys, High Energy Grp, Giessenbachstr, D-85741 Garching, Germany;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Guerrier, A.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Guiraud, J.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Gutierrez-Sanchez, R.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Haigron, R.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hatzidimitriou, D.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Hauser, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Haywood, M.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Helmi, A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Heu, J.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hilger, T.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Hobbs, D.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Hofmann, W.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Holland, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Huckle, H. E.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Hypki, A.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland;Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Icardi, V.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Janssen, K.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Jevardat de Fombelle, G.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Jonker, P. G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Juhasz, A. L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Eotvos Lorand Univ, Egyet Ter 1-3, H-1053 Budapest, Hungary.
    Julbe, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Karampelas, A.
    Amer Community Sch Athens, 129 Aghias Paraskevis Ave & Kazantzaki St, Athens 15234, Greece;Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Kewley, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Klar, J.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Kochoska, A.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia;Villanova Univ, Dept Astrophys & Planetary Sci, 800 Lancaster Ave, Villanova, PA 19085 USA.
    Kohley, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Kolenberg, K.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium;Univ Antwerp, Phys Dept, Groenenborgerlaan 171, B-2020 Antwerp, Belgium;Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA.
    Kontizas, M.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Kontizas, E.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Koposov, S. E.
    Carnegie Mellon Univ, McWilliams Ctr Cosmol, Dept Phys, 5000 Forbes Ave, Pittsburgh, PA 15213 USA;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Kordopatis, G.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Kostrzewa-Rutkowska, Z.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Koubsky, P.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Lambert, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Lanza, A. F.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Lasne, Y.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Lavigne, J. -B
    Le Fustec, Y.
    CNES Ctr Spatial Toulouse, Telespazio, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Le Poncin-Lafitte, C.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Lebreton, Y.
    Univ Rennes 1, Inst Phys Rennes, F-35042 Rennes, France;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Leccia, S.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Leclerc, N.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lecoeur-Taibi, I.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Lenhardt, H.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Leroux, F.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Liao, S.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China.
    Licata, E.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Lindstrom, H. E. P.
    Univ Copenhagen, Niels Bohr Inst, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark;DXC Technol, Retortvej 8, DK-2500 Valby, Denmark.
    Lister, T. A.
    Las Cumbres Observ, 6740 Cortona Dr Suite, Goleta, CA 93117 USA.
    Livanou, E.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Lobel, A.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Lopez, M.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Managau, S.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Mann, R. G.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mantelet, G.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Marchal, O.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Marchant, J. M.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Marconi, M.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Marinoni, S.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Marschalko, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Univ Szeged, Baja Observ, Szegedi Ut II 70, H-6500 Baja, Hungary.
    Marshall, D. J.
    Univ Paris Diderot, Lab AIM, IRFU Serv Astrophys, CEA DSM CNRS, Bat 709,CEA Saclay, F-91191 Gif Sur Yvette, France.
    Martino, M.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Marton, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Mary, N.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Massari, D.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Matijevic, G.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Mazeh, T.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    McMillan, P. J.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Messina, S.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Michalik, D.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Millar, N. R.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Molina, D.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Molinaro, R.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Molnar, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Montegriffo, P.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Mor, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Morbidelli, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Morel, T.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Morris, D.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mulone, A. F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Muraveva, T.
    Musella, I.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Nelemans, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Nicastro, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Noval, L.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    O'Mullane, W.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ordenovic, C.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Ordonez-Blanco, D.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Osborne, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Pagani, C.
    Univ Leicester, Dept Phys & Astron, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Pagano, I.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Pailler, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palacin, H.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palaversa, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Panahi, A.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Pawlak, M.
    Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland;Charles Univ Prague, Inst Theoret Phys, Fac Math & Phys, Prague, Czech Republic.
    Piersimoni, A. M.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Pineau, F. -X
    Plachy, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Plum, G.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Poggio, E.
    Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Poujoulet, E.
    CNES Ctr Spatial Toulouse, AKKA, 18 Ave Edouard Belin, F-31401 Toulouse 9, France;ESA ESTEC, HE Space Operat BV, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Prsa, A.
    Villanova Univ, Dept Astrophys & Planetary Sci, 800 Lancaster Ave, Villanova, PA 19085 USA.
    Pulone, L.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy.
    Racero, E.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ragaini, S.
    Rambaux, N.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Ramos-Lerate, M.
    ESA ESAC, Vitrociset Belgium, Camino Bajo Castillo S-N, Madrid 28692, Spain;Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA.
    Regibo, S.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Reyle, C.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Riclet, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Ripepi, V.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Riva, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Rivard, A.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Rixon, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Roegiers, T.
    ESA ESAC, QUASAR Sci Resources, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Roelens, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Romero-Gomez, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Rowell, N.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Royer, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ruiz-Dern, L.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Sadowski, G.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Sagrista Selles, T.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Sahlmann, J.
    Fork Res, Rua Cruzado Osberno,Lt 1,9 Esq, Lisbon, Portugal;ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Salgado, J.
    CNES Ctr Spatial Toulouse, APAVE SUDEUROPE SAS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Salguero, E.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Sanna, N.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Santana-Ros, T.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland.
    Sarasso, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Savietto, H.
    Nord Optic Telescope, Rambla Jose Ana Fernandez Perez 7, Brena Baja 38711, Spain.
    Schultheis, M.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Sciacca, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Segol, M.
    Spanish Virtual Observ, Santander, Spain.
    Segovia, J. C.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Segransan, D.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Shih, I-C
    Siltala, L.
    INAF, Fdn Galileo Galilei, Rambla Jose Ana Fernandez Perez 7, Brena Baja 38712, Santa Cruz Tene, Spain;Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Silva, A. F.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Smart, R. L.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Smith, K. W.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Solano, E.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain;ESA ESAC, INSA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Solitro, F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Sordo, R.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Soria Nieto, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Souchay, J.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Spagna, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Spoto, F.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France;Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Stampa, U.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Steele, I. A.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Steidelmueller, H.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Stephenson, C. A.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Stoev, H.
    Univ Complutense Madrid, Dept Arquitectura Computadores & Automat, Fac Informat, C Prof Jose Garcia Santesmases S-N, E-28040 Madrid, Spain.
    Suess, F. F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Surdej, J.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Szabados, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Szegedi-Elek, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Tapiador, D.
    Univ Bristol, HH Wills Phys Lab, Tyndall Ave, Bristol BS8, Avon, England;IEEC, Gran Capita 2-4,08034, Bristol BS8 1TL, Avon, England.
    Taris, F.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Tauran, G.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Taylor, M. B.
    Univ Vigo, Appl Phys Dept, Vigo 36310, Spain.
    Teixeira, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    Terrett, D.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Teyssandier, P.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Thuillot, W.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Titarenko, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Clotet, F. Torra
    Aarhus Univ, Stellar Astrophys Ctr, Dept Phys & Astron, 120 Ny Munkegade,Bldg 1520, DK-8000 Aarhus, Denmark.
    Turon, C.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ulla, A.
    Univ Bonn, Argelander Inst Astron, Hugel 71, D-53121 Bonn, Germany.
    Utrilla, E.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Uzzi, S.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Vaillant, M.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Valentini, G.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Valette, V.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    van Elteren, A.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Van Hemelryck, E.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Vaschetto, M.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Vecchiato, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Veljanoski, J.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Viala, Y.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Vicente, D.
    Ctr Nacl Super Comp, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus 2, Barcelona 08034, Spain.
    Vogt, S.
    ESA ESAC, QUASAR Sci Resources, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    von Essen, C.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Voss, H.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Votruba, V.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Voutsinas, S.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Walmsley, G.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Weiler, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Wertz, O.
    Sorbonne Univ, UPMC Univ, Paris 6 & CNRS, UMR 7095,Inst Astrophys Paris, 98 Bis Bd Arago, F-75014 Paris, France.
    Wevers, T.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Wyrzykowski, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland.
    Yoldas, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Zerjal, M.
    Tel Aviv Univ, Dept Geosci, IL-6997801 Tel Aviv, Israel;Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Ziaeepour, H.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Zorec, J.
    Zschocke, S.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Zucker, S.
    Zurbach, C.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 05, France.
    Zwitter, T.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Observational Hertzsprung-Russell diagrams2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A10Article in journal (Refereed)
    Abstract [en]

    Context. Gaia Data Release 2 provides high-precision astrometry and three-band photometry for about 1.3 billion sources over the full sky. The precision, accuracy, and homogeneity of both astrometry and photometry are unprecedented. Aims. We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples. Methods. We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects. Results. The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics. Conclusions. Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies.

  • 20. Bagnulo, S.
    et al.
    Fossati, L.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Landstreet, J. D.
    The importance of non-photon noise in stellar spectropolarimetry The spurious detection of a non-existing magnetic field in the AO supergiant HD 922072013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 559, p. A103-Article in journal (Refereed)
    Abstract [en]

    Context. The low-resolution, Cassegrain mounted, FORS spectropolarimeter of the ESO Very Large Telescope is being extensively used for magnetic field surveys. Some of the new discoveries suggest that relatively strong magnetic fields may play an important role in numerous physical phenomena observed in the atmospheres as well as in the circumstellar environments of certain kinds of stars. Aims. We show in detail how small instabilities or data-reduction inaccuracies represent an alternative explanation for the origin of certain signals of circular polarisation published in recent years. Methods. With the help of analytical calculations we simulate the observation of a spectral line in spectropolarimetric mode, adding very small spurious wavelength shifts, which may mimic the effects of seeing variations, rapid variations of the stellar radial velocity, or instrument instabilities. As a case study, we then re-visit the FORS2 measurements that have been used to claim the discovery of a magnetic field in the A0 supergiant HD 92207. In addition, we present new observations of this star obtained with the HARPSpol instrument. Results. Both calibration and science data show compelling evidence that photon-noise is not the only source of error in magnetic field measurements, especially in sharp spectral lines. Non-photon noise may be kept under control by accurate data reduction and quality controls. Our re-analysis of FORS2 observations of HD 92207 shows no evidence of a magnetic field, and we are able to reproduce the previous FORS detection only by degrading the quality of our wavelength calibration. Our HARPSpol spectropolarimetric measurements show no evidence of a magnetic field at the level of 10 G. Conclusions. Our work contributes to a better understanding of the importance of accurate data treatment and instrument characterisation, and demonstrates that ultra-high signal-to-noise ratio measurements do not automatically translate into ultra-high accuracy.

  • 21. Bagnulo, S.
    et al.
    Landstreet, J. D.
    Fossati, L.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Magnetic field measurements and their uncertainties: the FORS1 legacy2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 538, p. A129-Article in journal (Refereed)
    Abstract [en]

    Context. During the last decade, the FORS1 instrument of the ESO Very Large Telescope has been extensively used to study stellar magnetism. A number of interesting discoveries of magnetic fields in several classes of stars have been announced, many of which obtained at a similar to 3 sigma level; some of the discoveries are confirmed by measurements obtained with other instruments, some are not.

    Aims. We investigate the reasons for the discrepancies between the results obtained with FORS1 and those obtained with other instruments.

    Methods. Using the ESO FORS pipeline, we have developed a semi-automatic procedure for magnetic field determination. We have applied this procedure to the full content of circular spectropolarimetric measurements of the FORS1 archive (except for most of the observations obtained in multi-object spectropolarimetric mode). We have devised and applied a number of consistency checks to our field determinations, and we have compared our results to those previously published in the literature.

    Results. We find that for high signal-to-noise ratio measurements, photon noise does not account for the full error bars. We discuss how field measurements depend on the specific algorithm adopted for data reduction, and we show that very small instrument flexures, negligible in most of the instrument applications, may be responsible for some spurious field detections in the null profiles. Finally, we find that we are unable to reproduce some results previously published in the literature. Consequently, we do not confirm some important discoveries of magnetic fields obtained with FORS1 and reported in previous publications.

    Conclusions. Our revised field measurements show that there is no contradiction between the results obtained with the low-resolution spectropolarimeter FORS1 and those obtained with high-resolution spectropolarimeters. FORS1 is an instrument capable of performing reliable magnetic field measurements, provided that the various sources of uncertainties are properly taken into account.

  • 22. Bailer-Jones, C. A. L.
    et al.
    Andrae, R.
    Arcay, B.
    Astraatmadja, T.
    Bellas-Velidis, I.
    Berihuete, A.
    Bijaoui, A.
    Carrion, C.
    Dafonte, C.
    Damerdji, Y.
    Dapergolas, A.
    de Laverny, P.
    Delchambre, L.
    Drazinos, P.
    Drimmel, R.
    Fremat, Y.
    Fustes, D.
    Garcia-Torres, M.
    Guede, C.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Janotto, A. -M
    Karampelas, A.
    Kim, D. -W
    Knude, J.
    Kolka, I.
    Kontizas, E.
    Kontizas, M.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Lanzafame, A. C.
    Lebreton, Y.
    Lindstrom, H.
    Liu, C.
    Livanou, E.
    Lobel, A.
    Manteiga, M.
    Martayan, C.
    Ordenovic, Ch.
    Pichon, B.
    Recio-Blanco, A.
    Rocca-Volmerange, B.
    Sarro, L. M.
    Smith, K.
    Sordo, R.
    Soubiran, C.
    Surdej, J.
    Thevenin, F.
    Tsalmantza, P.
    Vallenari, A.
    Zorec, J.
    The Gaia astrophysical parameters inference system (Apsis) Pre-launch description2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 559, p. A74-Article in journal (Refereed)
    Abstract [en]

    The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred million stars. Its main objective is to take a census of the stellar content of our Galaxy, with the goal of revealing its formation and evolution. Gaia's unique feature is the measurement of parallaxes and proper motions with hitherto unparalleled accuracy for many objects. As a survey, the physical properties of most of these objects are unknown. Here we describe the data analysis system put together by the Gaia consortium to classify these objects and to infer their astrophysical properties using the satellite's data. This system covers single stars, (unresolved) binary stars, quasars, and galaxies, all covering a wide parameter space. Multiple methods are used for many types of stars, producing multiple results for the end user according to different models and assumptions. Prior to its application to real Gaia data the accuracy of these methods cannot be assessed definitively. But as an example of the current performance, we can attain internal accuracies (rms residuals) on F, G, K, M dwarfs and giants at G = 15 (V = 15-17) for a wide range of metallicites and interstellar extinctions of around 100 K in effective temperature (T-eff), 0.1 mag in extinction (A(0)), 0.2 dex in metallicity ([Fe/H]), and 0.25 dex in surface gravity (log g). The accuracy is a strong function of the parameters themselves, varying by a factor of more than two up or down over this parameter range. After its launch in December 2013, Gaia will nominally observe for five years, during which the system we describe will continue to evolve in light of experience with the real data.

  • 23. Bailey, J. D.
    et al.
    Landstreet, J. D.
    Bagnulo, S.
    Fossati, L.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Paladini, C.
    Silvester, J.
    Wade, G.
    Magnetic field and atmospheric chemical abundances of the magnetic Ap star HD 3181072011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 535, p. A25-Article in journal (Refereed)
    Abstract [en]

    Context. A new generation of powerful and efficient spectropolarimeters has recently been used to provide the first sample of magnetic Ap stars of accurately known ages. Modelling of these data offer the possibility of significant new insights into the physics and main sequence evolution of these remarkable stars.

    Aims. New spectra have been obtained with the ESPaDOnS spectropolarimeter, and are supplemented with unpolarised spectra from the ESO UVES, UVES-FLAMES, and HARPS spectrographs, of the very peculiar large-field magnetic Ap star HD 318107, a member of the open cluster NGC 6405 and thus a star with a well-determined age. The available data provide sufficient material with which to re-analyse the first-order model of the magnetic field geometry and to derive chemical abundances of Si, Ti, Fe, Nd, Pr, Mg, Cr, Mn, O, and Ca.

    Methods. The models were obtained using ZEEMAN, a program which synthesises spectral line profiles for stars that have magnetic fields. The magnetic field structure was modelled with a low-order colinear multipole expansion, using coefficients derived from the observed variations of the field strength with rotation phase. The abundances of several elements were determined using spectral synthesis. After experiments with a very simple model of uniform abundance on each of three rings of equal width in co-latitude and symmetric about the assumed magnetic axis, we decided to model the spectra assuming uniform abundances of each element over the stellar surface.

    Results. The new magnetic field measurements allow us to refine the rotation period of HD 318107 to P = 9.7088 +/- 0.0007 days. Appropriate magnetic field model parameters were found that very coarsely describe the (apparently rather complex) field moment variations. Spectrum synthesis leads to the derivation of mean abundances for the elements Mg, Si, Ca, Ti, Cr, Fe, Nd, and Pr. All of these elements except for Mg and Ca are strongly overabundant compared to the solar abundance ratios. There is considerable evidence of non-uniformity, for example in the different values of < B(z)> found using lines of different elements.

    Conclusions. The present data set, while limited, is nevertheless sufficient to provide a useful first-order assessment of both the magnetic and surface abundance properties of HD 318107, making it one of the very few magnetic Ap stars of well-known age for which both of these properties have been studied.

  • 24.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Electron-impact excitation of neutral oxygen2007In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 462, no 2, p. 781-788Article in journal (Refereed)
    Abstract [en]

    Aims.Our goal was to calculate transition rates from ground and excited states in neutral oxygen atoms due to electron collisions for non-LTE modelling of oxygen in late-type stellar atmospheres, thus enabling the reliable interpretation of oxygen lines in stellar spectra.Methods.A 38-state R-matrix calculation in LS-coupling has been performed. Basis orbitals from the literature are adopted, and a large set of configurations are included to obtain good representations of the target wave functions. Rate coefficients are calculated by averaging over a Maxwellian velocity distribution. Results.Estimates for the cross sections and rate coefficients are presented for transitions between the seven lowest LS states of neutral oxygen. The cross sections for excitation from the ground state compare well with existing experimental and recent theoretical results.

  • 25.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Excitation and charge transfer in low-energy hydrogen atom collisions with neutral oxygen2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 610, article id A57Article in journal (Refereed)
    Abstract [en]

    Excitation and charge transfer in low-energy O+H collisions is studied; it is a problem of importance for modelling stellar spectra and obtaining accurate oxygen abundances in late-type stars including the Sun. The collisions have been studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multichannel Landau-Zener model. The method has been extended to include configurations involving excited states of hydrogen using an estimate for the two-electron transition coupling, but this extension was found to not lead to any remarkably high rates. Rate coefficients are calculated for temperatures in the range 1000-20000 K, and charge transfer and (de) excitation processes involving the first excited S-states, 4s.S-5(0) and 4s.S-3(0), are found to have the highest rates.

  • 26.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Non-LTE Balmer line formation in late-type spectra: Effects of atomic processes involving hydrogen atoms2007In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 466, no 1, p. 327-337Article in journal (Refereed)
    Abstract [en]

    Context.The wings of Balmer lines are often used as effective temperature diagnostics for late-type (F, G, K) stars under the assumption they form in local thermodynamic equilibrium (LTE). Aims.Our goal is to investigate the non-LTE excitation and ionisation of hydrogen and the formation of Balmer lines in late-type stellar atmospheres, to establish if the assumption of LTE is justified. Furthermore, we aim to determine which collision processes are important for the problem; in particular, the role of collision processes with hydrogen atoms is investigated.Methods.A model hydrogen atom for non-LTE calculations has been constructed accounting for various collision processes using the best available data from the literature. The processes included are inelastic collisions with electrons and hydrogen atoms, mutual neutralisation and Penning ionisation. Non-LTE calculations are performed using the MULTI code and the MACKKL semi-empirical solar model, and the relative importance of the collision processes is investigated. Similar calculations are performed for MARCS theoretical models of other late-type stellar atmospheres.Results.Our calculations show electron collisions alone are not sufficient to establish LTE for the formation of Balmer line wings. Mutual neutralisation and Penning ionisation are found to be unimportant. The role of inelastic collisions with neutral hydrogen is unclear. The available data for these processes is of questionable quality, and different prescriptions for the rate coefficents give significantly different results for the Balmer line wings. Conclusions.Improved calculations or experimental data are needed for excitation and, particularly, ionisation of hydrogen atoms in low-lying states by hydrogen atom impact at near threshold energies. Until such data are available, the assumption of LTE for the formation of Balmer line wings in late-type stars is questionable.

  • 27.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Dickinson, A. S.
    Gadea, F. X.
    Inelastic Na+H collision data for non-LTE applications in stellar atmospheres2010In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 519, p. A20-Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for inelastic Na+H collisions are calculated for all transitions between the ten levels up to and including the ionic state (ion-pair production), namely Na(3s,3p,4s,3d,4p,5s,4d,4f,5p)+H(1s) and Na++H-. The calculations are based on recent full quantum scattering cross-section calculations. The data are needed for non-LTE applications in cool astrophysical environments, especially cool stellar atmospheres, and are presented for a temperature range of 500-8000 K. From consideration of the sensitivity of the cross-sections to input quantum chemical data and the results of different methods for the scattering calculations, a measure of the possible uncertainties in the rate coefficients is estimated.

  • 28.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Guitou, M.
    Feautrier, N.
    Gadea, F. X.
    Spielfiedel, A.
    On inelastic hydrogen atom collisions in stellar atmospheres2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 530, p. A94-Article in journal (Refereed)
    Abstract [en]

    The influence of inelastic hydrogen atom collisions on non-LTE spectral line formation has been, and remains to be, a significant source of uncertainty for stellar abundance analyses, due to the difficulty in obtaining accurate data for low-energy atomic collisions either experimentally or theoretically. For lack of a better alternative, the classical "Drawin formula" is often used. Over recent decades, our understanding of these collisions has improved markedly, predominantly through a number of detailed quantum mechanical calculations. In this paper, the Drawin formula is compared with the quantum mechanical calculations both in terms of the underlying physics and the resulting rate coefficients. It is shown that the Drawin formula does not contain the essential physics behind direct excitation by H atom collisions, the important physical mechanism being quantum mechanical in character. Quantitatively, the Drawin formula compares poorly with the results of the available quantum mechanical calculations, usually significantly overestimating the collision rates by amounts that vary markedly between transitions.

  • 29.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Spielfiedel, A.
    Guitou, M.
    Feautrier, N.
    Inelastic Mg plus H collision data for non-LTE applications in stellar atmospheres2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 541, p. A80-Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for inelastic Mg+H collisions are calculated for all transitions between the lowest seven levels and the ionic state (charge transfer), namely Mg(3s(2) S-1, 3s3p P-3, 3s3p P-1, 3s4s S-3, 3s4s S-1, 3s3d D-1, 3s4p P-3)+H(1s) and Mg+(3s S-2)+H-. The rate coefficients are based on cross-sections from full quantum scattering calculations, which are themselves based on detailed quantum chemical calculations for the MgH molecule. The data are needed for non-LTE applications in cool astrophysical environments, especially cool stellar atmospheres, and are presented for a temperature range of 500-8000 K. From consideration of the sensitivity of the cross-sections to various uncertainties in the calculations, most importantly input quantum chemical data and the numerical accuracy of the scattering calculations, a measure of the possible uncertainties in the rate coefficients is estimated.

  • 30.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Osorio, Y.
    Instituto de Astrofísica de Canarias, vía Láctea.; Universidad de La Laguna, Departamento de Astrofísica.; Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg.
    Fursa, D. V.
    Curtin Institute for Computation, Kent Street.; Department of Physics, Astronomy and Medical Radiation Science, Kent Street.
    Bray, I.
    Curtin Institute for Computation, Kent Street.; Department of Physics, Astronomy and Medical Radiation Science, Kent Street.
    Zatsarinny, O.
    Drake University, Department of Physics and Astronomy.
    Bartschat, K.
    Drake University, Department of Physics and Astronomy.
    Jerkstrand, A.
    Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching.
    Inelastic e plus Mg collision data and its impact on modelling stellar and supernova spectra2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 606, article id A11Article in journal (Refereed)
    Abstract [en]

    Results of calculations for inelastic e+Mg effective collision strengths for the lowest 25 physical states of Mg I (up to 3s6p P-1), and thus 300 transitions, from the convergent close-coupling (CCC) and the B-spline R-matrix (BSR) methods are presented. At temperatures of interest, similar to 5000 K, the results of the two calculations differ on average by only 4%,with a scatter of 27%. As the methods are independent, this suggests that the calculations provide datasets for e+Mg collisions accurate to this level. Comparison with the commonly used dataset compiled by Mauas et al. (1988, ApJ, 330, 1008), covering 25 transitions among 12 states, suggests the Mauas et al. data are on average similar to 57% too low, and with a very large scatter of a factor of similar to 6.5. In particular the collision strength for the transition corresponding to the Mg I intercombination line at 457 nm is significantly underestimated by Mauas et al., which has consequences for models that employ this dataset. In giant stars the new data leads to a stronger line compared to previous non-LTE calculations, and thus a reduction in the non-LTE abundance correction by similar to 0.1 dex (similar to 25%). A non-LTE calculation in a supernova ejecta model shows this line becomes significantly stronger, by a factor of around two, alleviating the discrepancy where the 457 nm line in typical models with Mg/O ratios close to solar tended to be too weak compared to observations.

  • 31.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A90Article in journal (Refereed)
    Abstract [en]

    Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multi-channel Landau-Zener model. An extensive calculation including 166 covalent states and 25 ionic states is presented and rate coefficients are calculated for temperatures in the range 1000-20 000 K. The largest rates are found for charge transfer processes to and from two clusters of states around 6.3 and 6.6 eV excitation, corresponding in both cases to active 4d and 5p electrons undergoing transfer. Excitation and de-excitation processes among these two sets of states are also significant.

  • 32.
    Barklem, Paul S.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Collet, R.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.;Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark..
    Partition functions and equilibrium constants for diatomic molecules and atoms of astrophysical interest2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 588, article id A96Article in journal (Refereed)
    Abstract [en]

    Partition functions and dissociation equilibrium constants are presented for 291 diatomic molecules for temperatures in the range from near absolute zero to 10 000 K, thus providing data for many diatomic molecules of astrophysical interest at low temperature. The calculations are based on molecular spectroscopic data from the book of Huber & Herzberg (1979, Constants of Diatomic Molecules) with significant improvements from the literature, especially updated data for ground states of many of the most important molecules by Irikura (2007, J. Phys. Chem. Ref. Data, 36, 389). Dissociation energies are collated from compilations of experimental and theoretical values. Partition functions for 284 species of atoms for all elements from H to U are also presented based on data collected at NIST. The calculated data are expected to be useful for modelling a range of low density astrophysical environments, especially star-forming regions, protoplanetary disks, the interstellar medium, and planetary and cool stellar atmospheres. The input data, which will be made available electronically, also provides a possible foundation for future improvement by the community.

  • 33.
    Barucci, M. A.
    et al.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Filacchione, G.
    INAF IAPS, I-00133 Rome, Italy..
    Fornasier, S.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Raponi, A.
    INAF IAPS, I-00133 Rome, Italy..
    Deshapriya, J. D. P.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Tosi, F.
    INAF IAPS, I-00133 Rome, Italy..
    Feller, C.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Ciarniello, M.
    INAF IAPS, I-00133 Rome, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Capaccioni, F.
    INAF IAPS, I-00133 Rome, Italy..
    Pommerol, A.
    Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Massironi, M.
    Univ Padua, Dipartimento Geosci, I-35122 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Merlin, F.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Vincent, J. -B
    Fulchignoni, M.
    Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Guilbert-Lepoutre, A.
    Observ Sci Univers, F-25000 Besancon, France..
    Perna, D.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Capria, M. T.
    INAF IAPS, I-00133 Rome, Italy..
    Hasselmann, P. H.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Rousseau, B.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Bockelee-Morvan, D.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Lamy, P. L.
    Aix Marseille Univ, F-13388 Marseille 13, France..
    De Sanctis, C.
    INAF IAPS, I-00133 Rome, Italy..
    Rodrigo, R.
    CSIC INTA, Ctr Astrobiol, Madrid 28850, Spain.;Univ Bern, Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Erard, S.
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 Noordwijk, Netherlands..
    Leyrat, C.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Bartycka 18A, PL-00716 Warsaw, Poland..
    Drossart, P.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Arnold, G.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Bertaux, J. -L
    Bertini, I.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Cerroni, P.
    INAF IAPS, I-00133 Rome, Italy..
    Cremonese, G.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    Univ Padua, Dept Informat Engn, Via Gradenigo 6, I-35131 Padua, Italy..
    Davidsson, B. J. R.
    JPL, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    El-Maarry, M. R.
    Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Fonti, S.
    Univ Salento, Dipartimento Fis, Lecce, LE, Italy..
    Fulle, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34143 Trieste, Italy..
    Groussin, O.
    CNRS, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W.
    Natl Cent Univ, Inst Space Sci, Chungli 32054, Taiwan..
    Jorda, L.
    CNRS, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Kappel, D.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    ESA ESAC, POB 78, Villanueva De La Canada 28691, Spain..
    Lara, L.
    CSIC, Inst Astrofis Andalucia, Granada 18080, Spain..
    Lazzarin, M.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Moreno, J. J. Lopez
    CSIC, Inst Astrofis Andalucia, Granada 18080, Spain..
    Mancarella, F.
    Univ Salento, Dipartimento Fis, Lecce, LE, Italy..
    Marzari, F.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Mottola, S.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Naletto, G.
    Univ Padua, Dept Informat Engn, Via Gradenigo 6, I-35131 Padua, Italy..
    Pajola, M.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Palomba, E.
    INAF IAPS, I-00133 Rome, Italy..
    Quirico, E.
    UJF Grenoble 1, CNRS INSU, F-38400 St Martin Dheres, France..
    Schmitt, B.
    UJF Grenoble 1, CNRS INSU, F-38400 St Martin Dheres, France..
    Thomas, N.
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Detection of exposed H2O ice on the nucleus of comet 67P/Churyumov-Gerasimenko as observed by Rosetta OSIRIS and VIRTIS instruments2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 595, article id A102Article in journal (Refereed)
    Abstract [en]

    Context. Since the orbital insertion of the Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus. Aims. The aim of this work is to search for the presence of H2O on the nucleus which, in general, appears very dark and rich in dehydrated organic material. After selecting images of the bright spots which could be good candidates to search for H2O ice, taken at high resolution by OSIRIS, we check for spectral cubes of the selected coordinates to identify these spots observed by VIRTIS. Methods. The selected OSIRIS images were processed with the OSIRIS standard pipeline and corrected for the illumination conditions for each pixel using the Lommel-Seeliger disk law. The spots with higher I/F were selected and then analysed spectrophotometrically and compared with the surrounding area. We selected 13 spots as good targets to be analysed by VIRTIS to search for the 2 mu m absorption band of water ice in the VIRTIS spectral cubes. Results. Out of the 13 selected bright spots, eight of them present positive H2O ice detection on the VIRTIS data. A spectral analysis was performed and the approximate temperature of each spot was computed. The H2O ice content was confirmed by modeling the spectra with mixing (areal and intimate) of H2O ice and dark terrain, using Hapke's radiative transfer modeling. We also present a detailed analysis of the detected spots.

  • 34.
    Belyaev, Andrey K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Inelastic aluminium-hydrogen collision data for non-LTE applications in stellar atmospheres2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 560, p. A60-Article in journal (Refereed)
    Abstract [en]

    Aims. Rate coefficients for inelastic Al + H and Al+ + H- collisions are calculated for all transitions between the seven low-lying levels up to and including the ionic state, namely Al(3p, 4s, 3d, 4p, 5s, nd)+H(1s) and Al+ + H-. The data are needed for non-LTE applications in stellar atmospheres and are presented for a temperature range of 1000-10 000 K.

    Methods. The calculations were obtained by means of the recently proposed model approach based on the asymptotic method for electronic molecular structure determination and on the branching probability current method for the nonadiabatic nuclear dynamics.

    Results. It is shown that the processes with the highest rates are the excitation and de-excitation ones between the Al(3d), Al(4p) and Al(4s) states in collisions with H, as well as the ion-pair formation and the mutual neutralization processes between these states and the ionic state.

  • 35.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Yakovleva, Svetlana A.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Inelastic silicon-hydrogen collision data for non-LTE applications in stellar atmospheres2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 572, p. A103-Article in journal (Refereed)
    Abstract [en]

    Aims. Inelastic processes in low-energy Si + H and Si+ + H- collisions are treated for the states from the ground state up to the ionic state, in order to provide rate coefficients needed for non-LTE modeling of Si in cool stellar atmospheres. Methods. Electronic molecular structure is determined using a recently proposed model approach based on an asymptotic method in combination with available ab initio potentials. Nonadiabatic nuclear dynamics are treated by means of a combination of multichannel formulas and the branching-probability-current method, based on the Landau-Zener model for nonadiabatic transition probabilities. Results. Cross sections and rate coefficients for inelastic processes in Si + H and Si+ + H- collisions for all transitions between 26 low-lying states plus the ionic state are calculated. It is shown that the highest rate coefficient values correspond to the excitation, de-excitation, ion-pair formation, and mutual neutralization processes involving the Si(3p4p D-3), Si(3p3d F-3), Si(3p4p D-1), Si(3p3d P-3), Si(3p4p S-1), and the ionic Si+ + H- states. These processes are likely to be important in non-LTE modeling.

  • 36.
    Bensby, Thomas
    et al.
    Lund Observ, Dept Astron & Theoret Phys, Lund, Sweden.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Max Planck Inst Astron, Heidelberg, Germany.
    Exploring the production and depletion of lithium in the Milky Way stellar disk2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 615, article id A151Article in journal (Refereed)
    Abstract [en]

    Despite the recent availability of large samples of stars with high-precision Li abundances, there are many unanswered questions about the evolution of this unique element in the Galaxy and in the stars themselves. It is unclear which parameters and physical mechanisms govern Li depletion in late-type stars and if Galactic enrichment has proceeded differently in different stellar populations. With this study we aim to explore these questions further by mapping the evolution of Li with stellar mass, age, and effective temperature for Milky Way disk stars, linking the metal-poor and metal-rich regimes, and how Li differs in the thin and thick disks. We determine Li abundances for a well-studied sample of 714 F and G dwarf, turn-off, and subgiant stars in the solar neighbourhood. The analysis is based on line synthesis of the Li-7 line at 6707 angstrom in high-resolution and high-signal-to-noise ratio echelle spectra, obtained with the MIKE, FEROS, SOFIN, UVES, and FIES spectrographs. The presented Li abundances are corrected for non-LTE effects. Out of the sample of 714 stars, we are able to determine Li abundances for 394 stars and upper limits on the Li abundance for another 121 stars. Out of 36 stars that are listed as exoplanet host stars, 18 have well-determined Li abundances and 6 have Li upper limits. Our main finding is that there are no signatures of Li production in stars associated with the thick disk. Instead the Li abundance trend is decreasing with metallicity for these thick disk stars. Significant Li production is however seen in the thin disk, with a steady increase towards super-solar metallicities. At the highest metallicities, however, around [Fe/H] approximate to +0.3, we tentatively confirm the recent discovery that the Li abundances level out. Our finding contradicts the other recent studies that found that Li is also produced in the thick disk. We find that this is likely due to the alpha-enhancement criteria which those studies used to define their thick disk samples. By using the more robust age criteria, we are able to define a thick disk stellar sample that is much less contaminated by thin disk stars. Furthermore, we also tentatively confirm the age-Li correlation for solar twin stars, and we find that there is no correlation between Li abundance and whether the stars have detected exoplanets or not. The major conclusion that can be drawn from this study is that no significant Li production relative to the primordial abundance took place during the first few billion years of the Milky Way, an era coinciding with the formation and evolution of the thick disk. Significant Li enrichment then took place once long-lived low-mass stars (acting on a timescale longer than SNIa) had had time to contribute to the chemical enrichment of the interstellar medium.

  • 37. Bergemann, M.
    et al.
    Ruchti, G. R.
    Serenelli, A.
    Feltzing, S.
    Alves-Brito, A.
    Asplund, M.
    Bensby, T.
    Gruyters, Pieter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Hourihane, A.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Lind, K.
    Marino, A.
    Jofre, P.
    Nordlander, T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ryde, N.
    Worley, C. C.
    Gilmore, G.
    Randich, S.
    Ferguson, A. M. N.
    Jeffries, R. D.
    Micela, G.
    Negueruela, I.
    Prusti, T.
    Rix, H. -W
    Vallenari, A.
    Alfaro, E. J.
    Allende Prieto, C.
    Bragaglia, A.
    Koposov, S. E.
    Lanzafame, A. C.
    Pancino, E.
    Recio-Blanco, A.
    Smiljanic, R.
    Walton, N.
    Costado, M. T.
    Franciosini, E.
    Hill, V.
    Lardo, C.
    de Laverny, P.
    Magrini, L.
    Maiorca, E.
    Masseron, T.
    Morbidelli, L.
    Sacco, G.
    Kordopatis, G.
    Tautvaisiene, G.
    The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 565, p. A89-Article in journal (Refereed)
    Abstract [en]

    We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 < vertical bar Z vertical bar < 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages > 9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more alpha-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars.

  • 38.
    Bergemann, Maria
    et al.
    Max Planck Inst Astron, D-69117 Heidelberg, Germany..
    Serenelli, Aldo
    Campus UAB, ICE CSIC IEEC, Inst Ciencias Espacio, Carrer Can Magrans S-N, Bellaterra 08193, Spain..
    Schonrich, Ralph
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, 1 Keble Rd, Oxford OX1 3NP, England..
    Ruchti, Greg
    Lund Observ, Box 43, S-22100 Lund, Sweden..
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala Univ, Div Astron & Space Phys, Dept Phys & Astron, Angstrom Lab, Box 516, S-75120 Uppsala, Sweden..
    Hekker, Saskia
    Max Planck Inst Solar Syst Res, Justus von Liebig Weg 3, D-37077 Gttingen, Germany..
    Kovalev, Mikhail
    Max Planck Inst Astron, D-69117 Heidelberg, Germany..
    Mashonkina, Lyudmila
    Gilmore, Gerry
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Randich, Sofia
    INAF Osservatorio Astrofis Arcetri, Largo Fermi 5, I-50125 Florence, Italy..
    Asplund, Martin
    Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia..
    Rix, Hans-Walter
    Max Planck Inst Astron, D-69117 Heidelberg, Germany..
    Casey, Andrew R.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Jofre, Paula
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Pancino, Elena
    INAF Osservatorio Astron, Via Ranzani 1, I-40127 Bologna, Italy.;ASI Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy..
    Recio-Blanco, Alejandra
    Univ Nice Sophia Antipolis, CNRS, Observ Cote Azur, Lab Lagrange, BP 4229, F-06304 Nice 4, France..
    de Laverny, Patrick
    Univ Nice Sophia Antipolis, CNRS, Observ Cote Azur, Lab Lagrange, BP 4229, F-06304 Nice 4, France..
    Smiljanic, Rodolfo
    Nicolaus Copernicus Astron Ctr, Dept Astrophys, Ul Rabianska 8, PL-87100 Torun, Poland. Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munckegade 120, DK-8000 Aarhus, Denmark..
    Tautvaisiene, Grazina
    Vilnius Univ, Inst Theoret Phys & Astron, Gostauto 12, LT-01108 Vilnius, Lithuania..
    Bayo, Amelia
    Inst Fis & Astron, Fac Ciencias, Gran Bretana 1111, Playa Ancha, Chile..
    Lewis, Jim
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Koposov, Sergey
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Hourihane, Anna
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Worley, Clare
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Morbidelli, Lorenzo
    INAF Osservatorio Astrofis Arcetri, Largo Fermi 5, I-50125 Florence, Italy..
    Franciosini, Elena
    INAF Osservatorio Astrofis Arcetri, Largo Fermi 5, I-50125 Florence, Italy..
    Sacco, Germano
    INAF Osservatorio Astrofis Arcetri, Largo Fermi 5, I-50125 Florence, Italy..
    Magrini, Laura
    INAF Osservatorio Astrofis Arcetri, Largo Fermi 5, I-50125 Florence, Italy..
    Damiani, Francesco
    INAF Osservatorio Astron Palermo, Piazza Parlamento 1, I-90134 Palermo, Italy. Russian Acad Sci, Inst Astron, Pyatnitskaya St 48, Moscow 119017, Russia..
    Bestenlehner, Joachim M.
    The Gaia-ESO Survey: Hydrogen lines in red giants directly trace stellar mass2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 594, article id A120Article in journal (Refereed)
    Abstract [en]

    Red giant stars are perhaps the most important type of stars for Galactic and extra-galactic archaeology: they are luminous, occur in all stellar populations, and their surface temperatures allow precise abundance determinations for many different chemical elements. Yet, the full star formation and enrichment history of a galaxy can be traced directly only if two key observables can be determined for large stellar samples: age and chemical composition. While spectroscopy is a powerful method to analyse the detailed abundances of stars, stellar ages are the missing link in the chain, since they are not a direct observable. However, spectroscopy should be able to estimate stellar masses, which for red giants directly infer ages provided their chemical composition is known. Here we establish a new empirical relation between the shape of the hydrogen line in the observed spectra of red giants and stellar mass determined from asteroseismology. The relation allows determining stellar masses and ages with an accuracy of 10-15%. The method can be used with confidence for stars in the following range of stellar parameters: 4000 < T-eff < 5000 K, 0.5 < log g < 3.5, -2.0 < [ Fe/H] < 0.3, and luminosities log L/L-Sun < 2.5. Our analysis provides observational evidence that the H-alpha spectral characteristics of red giant stars are tightly correlated with their mass and therefore their age. We also show that the method samples well all stellar populations with ages above 1 Gyr. Targeting bright giants, the method allows obtaining simultaneous age and chemical abundance information far deeper than would be possible with asteroseismology, extending the possible survey volume to remote regions of the Milky Way and even to neighbouring galaxies such as Andromeda or the Magellanic Clouds even with current instrumentation, such as the VLT and Keck facilities.

  • 39.
    Bergvall, Nils
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Leitet, Elisabet
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Zackrisson, Erik
    Department of Astronomy, Stockholm University, Oscar Klein Center, AlbaNova, Stockholm.
    Marquart, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Lyman continuum leaking galaxies: Search strategies and local candidates2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 554, p. A38-Article in journal (Other academic)
    Abstract [en]

    Context. Star-forming dwarf galaxies may have played an important role in the reionization of the Universe, provided that some fraction of their ionizing radiation were able to escape into the intergalactic medium. Local galaxies exhibiting such Lyman-continuum(LyC) leakage could potentially shed light on the escape mechanisms involved, but only two low-redshift cases of LyC leakage have been identified so far. Here, we argue that this meager harvest may be caused by unsuitable selection criteria. Candidates for LyC leakage are normally selected by indicators of starburst activity, one of which is a high equivalent width in H alpha. Such a criterion will guarantee a high production of LyC photons but will also bias the selection in favour of a high column density in the neutral gas, effectively ruling out LyC escape. Aims. In this work we want to investigate whether the lack of local LyC emitters can be caused in part by biased selection criteria, and we present a novel method of selecting targets with high escape fractions. By applying these criteria, we assemble a sample of observation targets to study their basic properties. Methods. We introduce a new selection strategy here where the potential LyC leakers are selected by their blue colours and weak emission lines. The selection is based on data from the Sloan Digital Sky Survey (SDSS). We also take a closer look at the properties of 8 LyCleaking candidates at z similar to 0.03 which we have observed with ESO/NTT in broadband B and H alpha. Results. We find that 7 of the 8 target galaxies are involved in interaction with neighbours or show signs of mergers. In 7 cases the young stellar population is clearly displaced relative to the main body of these galaxies, often directly bordering the halo region. In about half of our targets the absorption spectra show young post-starburst signatures. Comparing the scale lengths in H alpha with those of the stellar continua shows that the scale lengths in H alpha typically are 30% smaller, which is characteristic of galaxies influenced by ram pressure stripping. We tentatively identify a few mechanisms that could improve the conditions for leakage: 1) the combined effects of ram pressure stripping with supernova winds from young stars formed in the front, 2) merger events that increase the star formation rate and displace stars from gas, 3) starbursts in the centres of post-starburst galaxies, whose previous activity has cleared channels for leakage into the intergalactic medium, and 4) a low dust content. Although our target galaxies are rare species in the local universe, we argue that related types could have played a major role in producing ionizing radiation at high redshifts.

  • 40.
    Bergvall, Nils
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Marquart, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Way, Michael J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. NASA Goddard Institute for Space Studies, 2880 Broadway, New York 10025, USA.
    Blomqvist, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Holst, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Östlin, Göran
    Stockholm Univ, Dept Astron, S-10691 Stockholm, Sweden.
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Local starburst galaxies and their descendants: Statistics from the Sloan Digital Sky Survey2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 587, article id A72Article in journal (Refereed)
    Abstract [en]

    Aims: Despite strong interest in the starburst phenomenon in extragalactic astronomy, the concept remains ill-defined. Here we use a strict definition of starburst to examine the statistical properties of starburst galaxies in the local universe. We also seek to establish links between starburst galaxies, post-starburst (hereafter postburst) galaxies, and active galaxies.

    Methods: Data were selected from the Sloan Digital Sky Survey DR7. We applied a novel method of treating dust attenuation and derive star formation rates, ages, and stellar masses assuming a two-component stellar population model. Dynamical masses are calculated from the width of the H alpha line. These masses agree excellently with the photometric masses. The mass (gas + stars) range is similar to 10(9)-10(11.5) M-circle dot. As a selection criterion for starburst galaxies, we use, the birthrate parameter, b = SFR/< SFR >, requiring that b >= 3. For postburst galaxies, we use, the equivalent width of H delta in absorption with the criterion EWH delta,abs >= 6 angstrom.

    Results: We find that only 1% of star-forming galaxies are starburst galaxies. They contribute 3 6% to the stellar production and are therefore unimportant for the local star formation activity. The median starburst age is 70 Myr roughly independent of mass, indicating that star formation is mainly regulated by local feedback processes. The b-parameter strongly depends on burst age. Values close to b = 60 are found at ages similar to 10 Myr, while almost no starbursts are found at ages >1 Gyr. The median baryonic burst mass fraction of sub-L* galaxies is 5% and decreases slowly towards high masses. The median mass fraction of the recent burst in the postburst sample is 5-10%. A smaller fraction of the postburst galaxies, however, originates in non-bursting galaxies. The age-mass distribution of the postburst progenitors (with mass fractions >3%) is bimodal with a break at log M (M-circle dot) similar to 10.6, above which the ages are doubled. The starburst and postburst luminosity functions (LFs) follow each other closely until M-r similar to -21, when active galactic nuclei (AGNs) begin to dominate. The postburst LF continues to follow the AGN LF, while starbursts become less significant. This suggests that the number of luminous starbursts is underestimated by about one dex at high luminosities, because of having large amounts of dust and/or being outshone by an AGN. It also indicates that the starburst phase preceded the AGN phase. Finally, we look at the conditions for global gas outflow caused by stellar feedback and find that massive starburst galaxies are susceptible to such outflows.

  • 41.
    Bertini, I.
    et al.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Moreno, F.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Pajola, M.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    La Forgia, F.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Lamy, P.
    CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Rodrigo, R.
    CSIC INTA, Ctr Astrobiol, Madrid 28850, Spain.;Int Space Sci Inst, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Keller, H. U.
    Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Observ Paris, F-92195 Meudon Pricipal, France..
    Bertaux, J. -L
    Cremonese, G.
    INAF Osservatorio Astron Padova, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Debei, S.
    Univ Padua, Dept Ind Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trent, UNITN, I-38100 Trento, Italy..
    Ferri, F.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Observ Paris, F-92195 Meudon Pricipal, France.;Univ Paris Diderot, Sorbonne Paris Cite, F-75205 Paris 13, France..
    Fulle, M.
    INAF Osservatorio Astron Trieste, I-34143 Trieste, Italy..
    Giacomini, L.
    Univ Padua, Dept Geosci, I-35131 Padua, Italy..
    Groussin, O.
    Aix Marseille Univ, CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille, France..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S. F.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Ip, W. -H
    Jorda, L.
    Aix Marseille Univ, CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille, France..
    Knollenberg, J.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kramm, J. R.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kuehrt, E.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kueppers, M.
    ESA ESAC, Villanueva De La Canada 28691, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Magrin, S.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Massironi, M.
    Univ Padua, Dept Geosci, I-35131 Padua, Italy..
    Michalik, H.
    Inst Datentech & Kommunikat Netze, D-38106 Braunschweig, Germany..
    Mottola, S.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Naletto, G.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy.;CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Search for satellites near comet 67P/Churyumov-Gerasimenko using Rosetta/OSIRIS images2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 583, article id A19Article in journal (Refereed)
    Abstract [en]

    Context. The European Space Agency Rosetta mission reached and started escorting its main target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, at the beginning of August 2014. Within the context of solar system small bodies, satellite searches from approaching spacecraft were extensively used in the past to study the nature of the visited bodies and their collisional environment. Aims. During the approaching phase to the comet in July 2014, the OSIRIS instrument onboard Rosetta performed a campaign aimed at detecting objects in the vicinity of the comet nucleus and at measuring these objects' possible bound orbits. In addition to the scientific purpose, the search also focused on spacecraft security to avoid hazardous material in the comet's environment. Methods. Images in the red spectral domain were acquired with the OSIRIS Narrow Angle Camera, when the spacecraft was at a distance between 5785 km and 5463 km to the comet, following an observational strategy tailored to maximize the scientific outcome. From the acquired images, sources were extracted and displayed to search for plausible displacements of all sources from image to image. After stars were identified, the remaining sources were thoroughly analyzed. To place constraints on the expected displacements of a potential satellite, we performed Monte Carlo simulations on the apparent motion of potential satellites within the Hill sphere. Results. We found no unambiguous detections of objects larger than similar to 6 m within similar to 20 km and larger than similar to 1 m between similar to 20 km and similar to 110 km from the nucleus, using images with an exposure time of 0.14 s and 1.36 s, respectively. Our conclusions are consistent with independent works on dust grains in the comet coma and on boulders counting on the nucleus surface. Moreover, our analysis shows that the comet outburst detected at the end of April 2014 was not strong enough to eject large objects and to place them into a stable orbit around the nucleus. Our findings underline that it is highly unlikely that large objects survive for a long time around cometary nuclei.

  • 42.
    Bladh, S.
    et al.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Paladini, C.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium..
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Aringer, B.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Tomography of silicate dust around M-type AGB stars I. Diagnostics based on dynamical models2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 607, article id A27Article in journal (Refereed)
    Abstract [en]

    Context: The heavy mass loss observed in evolved asymptotic giant branch stars is usually attributed to a two-step process: atmospheric levitation by pulsation-induced shock waves, followed by radiative acceleration of newly formed dust grains. Detailed wind models suggest that the outflows of M-type AGB stars may be triggered by photon scattering on Fe-free silicates with grain sizes of about 0.1-1 mu m. As a consequence of the low grain temperature, these Fe-free silicates can condense close to the star, but they do not produce the characteristic mid-IR features that are often observed in M-type AGB stars. However, it is probable that the silicate grains are gradually enriched with Fe as they move away from the star, to a degree where the grain temperature stays below the sublimation temperature, but is high enough to produce emission features.

    Aims: We investigate whether differences in grain temperature in the inner wind region, which are related to changes in the grain composition, can be detected with current interferometric techniques, in order to put constraints on the wind mechanism.

    Methods: We use phase-dependent radial structures of the atmosphere and wind of an M-type AGB star, produced with the 1D radiation-hydrodynamical code DARWIN, to investigate if current interferometric techniques can differentiate between the temperature structures that give rise to the same overall spectral energy distribution.

    Results: The spectral energy distribution is found to be a poor indicator of different temperature profiles and therefore is not a good tool for distinguishing different scenarios of changing grain composition. However, spatially resolved interferometric observations have promising potential. They show signatures even for Fe-free silicates (found at 2-3 stellar radii), in contrast to the spectral energy distribution. Observations with baselines that probe spatial scales of about 4 stellar radii and beyond are suitable for tracing changes in grain composition, since this is where effects of Fe enrichment should be found.

  • 43.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants: I. Basic criteria and dynamical models of M-type AGB stars2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 546, p. A76-Article in journal (Refereed)
    Abstract [en]

    Context. The heavy mass loss observed in evolved asymptotic giant branch stars is usually attributed to a two-stage process: atmospheric levitation by pulsation-induced shock waves followed by radiative acceleration of dust grains, which transfer momentum to the surrounding gas through collisions. In order for an outflow to occur the two stages of the mass-loss scheme have to connect, i.e., the radiative acceleration can only be initiated if the levitated gas reaches a distance from the stellar photosphere where dust particles can condense. This levitation distance is limited by the kinetic energy transferred to the gas by the shock waves, which imposes strict constraints on potential wind-driving dust species. Aims. This work is part of an ongoing effort aiming at identifying the actual wind-drivers among the dust species observed in circumstellar envelopes. In particular, we focus on the interplay between a strong stellar radiation field and the dust formation process. Methods. To identify critical properties of potential wind-driving dust species we use detailed radiation-hydrodynamical models which include a parameterized dust description, complemented by simple analytical estimates to help with the physical interpretation of the numerical results. The adopted dust description is constructed to mimic different chemical and optical dust properties in order to systematically study the effects of a realistic radiation field on the second stage of the mass loss mechanism. Results. We see distinct trends in which combinations of optical and chemical dust properties are needed to trigger an outflow. Dust species with a low condensation temperature and a near-infrared absorption coefficient that decreases strongly with wavelength will not condense close enough to the stellar surface to be considered as potential wind-drivers. Conclusions. Our models confirm that metallic iron and Fe-bearing silicates are not viable as wind-drivers due to their near-infrared optical properties and resulting large condensation distances. TiO2 is also excluded as a wind-driver due to the low abundance of Ti. Other species, such a SiO2 and Al2O3, are less clear-cut cases due to uncertainties in the optical and chemical data and further work is needed. A strong candidate is Mg2SiO4 with grain sizes of 0.1-1 mu m, where scattering contributes significantly to the radiative acceleration, as suggested by earlier theoretical work and supported by recent observations.

  • 44.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Nowotny, W.
    Aringer, B.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants II. Constraints from photometry of M-type AGB stars2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 553, p. A20-Article in journal (Refereed)
    Abstract [en]

    Context. The heavy mass loss observed in evolved asymptotic giant branch (AGB) stars is usually attributed to a two-stage process: atmospheric levitation by pulsation-induced shock waves, followed by radiative acceleration of newly formed dust grains. The dust transfers momentum to the surrounding gas through collisions and thereby triggers a general outflow. Radiation-hydrodynamical models of M-type AGB stars suggest that these winds can be driven by photon scattering - in contrast to absorption - on Fe-free silicate grains of sizes 0.1-1 mu m. Aims. In this paper we study photometric constraints for wind-driving dust species in M-type AGB stars, as part of an ongoing effort to identify likely candidates among the grain materials observed in circumstellar envelopes. Methods. To investigate the scenario of stellar winds driven by photon scattering on dust, and to explore how different optical and chemical properties of wind-driving dust species affect photometry we focus on two sets of dynamical models atmospheres: (i) models using a detailed description for the growth of Mg2SiO4 grains, taking into account both scattering and absorption cross-sections when calculating the radiative acceleration; and (ii) models using a parameterized dust description, constructed to represent different chemical and optical dust properties. By comparing synthetic photometry from these two sets of models to observations of M-type AGB stars we can provide constraints on the properties of wind-driving dust species. Results. Photometry from wind models with a detailed description for the growth of Mg2SiO4 grains reproduces well both the values and the time-dependent behavior of observations of M-type AGB stars, providing further support for the scenario of winds driven by photon scattering on dust. The photometry from the models with a parameterized dust description suggests that wind-drivers need to have a low absorption cross-section in the visual and near-IR to reproduce the time-dependent behavior, i. e. small variations in (J-K) and spanning a larger range in (V-K). This places constraints on the optical and chemical properties of the wind-driving dust species. Conclusions. To reproduce the observed photometric variations in (V-K) and (J-K) both detailed and parameterized models suggest that the wind-driving dust materials have to be quite transparent in the visual and near-IR. Consequently, strong candidates for outflows driven by photon scattering on dust grains are Mg2SiO4, MgSiO3, and potentially SiO2.

  • 45.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, Theoretical Astrophysics.
    Susanne, Höfner
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Aringer, Bernhard
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants III: Wind models for M-type AGB stars2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 575, article id A105Article in journal (Refereed)
  • 46. Blanco-Cuaresma, S.
    et al.
    Soubiran, C.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Asplund, M.
    Carraro, G.
    Costado, M. T.
    Feltzing, S.
    Gonzalez-Hernandez, J. I.
    Jimenez-Esteban, F.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Marino, A. F.
    Montes, D.
    San Roman, I.
    Tabernero, H. M.
    Tautvaisiene, G.
    Testing the chemical tagging technique with open clusters2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 577, article id A47Article in journal (Refereed)
    Abstract [en]

    Context. Stars are born together from giant molecular clouds and, if we assume that the priors were chemically homogeneous and well-mixed, we expect them to share the same chemical composition. Most of the stellar aggregates are disrupted while orbiting the Galaxy and most of the dynamic information is lost, thus the only possibility of reconstructing the stellar formation history is to analyze the chemical abundances that we observe today. Aims. The chemical tagging technique aims to recover disrupted stellar clusters based merely on their chemical composition. We evaluate the viability of this technique to recover co-natal stars that are no longer gravitationally bound. Methods. Open clusters are co-natal aggregates that have managed to survive together. We compiled stellar spectra from 31 old and intermediate-age open clusters, homogeneously derived atmospheric parameters, and 17 abundance species, and applied machine learning algorithms to group the stars based on their chemical composition. This approach allows us to evaluate the viability and efficiency of the chemical tagging technique. Results. We found that stars at different evolutionary stages have distinct chemical patterns that may be due to NLTE effects, atomic diffusion, mixing, and biases. When separating stars into dwarfs and giants, we observed that a few open clusters show distinct chemical signatures while the majority show a high degree of overlap. This limits the recovery of co-natal aggregates by applying the chemical tagging technique. Nevertheless, there is room for improvement if more elements are included and models are improved.

  • 47. Blanco-Cuaresma, S.
    et al.
    Soubiran, C.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Jofre, P.
    Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 569, p. A111-Article in journal (Refereed)
    Abstract [en]

    Context. An increasing number of high-resolution stellar spectra is available today thanks to many past and ongoing extensive spectroscopic surveys. Consequently, the scientific community needs automatic procedures to derive atmospheric parameters and individual element abundances. Aims. Based on the widely known SPECTRUM code by R.O. Gray, we developed an integrated spectroscopic software framework suitable for the determination of atmospheric parameters (i.e., effective temperature, surface gravity, metallicity) and individual chemical abundances. The code, named iSpec and freely distributed, is written mainly in Python and can be used on different platforms. Methods. iSpec can derive atmospheric parameters by using the synthetic spectral fitting technique and the equivalent width method. We validated the performance of both approaches by developing two different pipelines and analyzing the Gaia FGK benchmark stars spectral library. The analysis was complemented with several tests designed to assess other aspects, such as the interpolation of model atmospheres and the performance with lower quality spectra. Results. We provide a code ready to perform automatic stellar spectral analysis. We successfully assessed the results obtained for FGK stars with high-resolution and high signal-to-noise spectra.

  • 48. Blanco-Cuaresma, S.
    et al.
    Soubiran, C.
    Jofre, P.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    The Gaia FGK benchmark stars High resolution spectral library2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 566, p. A98-Article in journal (Refereed)
    Abstract [en]

    Context. An increasing number of high-resolution stellar spectra is available today thanks to many past and ongoing spectroscopic surveys. Consequently, numerous methods have been developed to perform an automatic spectral analysis on a massive amount of data. When reviewing published results, biases arise and they need to be addressed and minimized. Aims. We are providing a homogeneous library with a common set of calibration stars (known as the Gaia FGK benchmark stars) that will allow us to assess stellar analysis methods and calibrate spectroscopic surveys. Methods. High-resolution and signal-to-noise spectra were compiled from different instruments. We developed an automatic process to homogenize the observed data and assess the quality of the resulting library. Results. We built a high-quality library that will facilitate the assessment of spectral analyses and the calibration of present and future spectroscopic surveys. The automation of the process minimizes the human subjectivity and ensures reproducibility. Additionally, it allows us to quickly adapt the library to specific needs that can arise from future spectroscopic analyses.

  • 49.
    Bonifacio, P.
    et al.
    PSL Res Univ, CNRS, Observ Paris, GEPI, Pl Jules Janssen, F-92195 Meudon, France.
    Caffau, E.
    PSL Res Univ, CNRS, Observ Paris, GEPI, Pl Jules Janssen, F-92195 Meudon, France.
    Ludwig, H. -G
    Steffen, M.
    PSL Res Univ, CNRS, Observ Paris, GEPI, Pl Jules Janssen, F-92195 Meudon, France;Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Castelli, F.
    Ist Nazl Astrofis, Osservatorio Astron Trieste, Via Tiepolo 11, I-34131 Trieste, Italy.
    Gallagher, A. J.
    PSL Res Univ, CNRS, Observ Paris, GEPI, Pl Jules Janssen, F-92195 Meudon, France;Max Planck Inst Astron, D-69117 Heidelberg, Germany.
    Kucinskas, A.
    Vilnius Univ, Inst Theoret Phys & Astron, Astron Observ, Sauletekio Al 3, LT-10257 Vilnius, Lithuania.
    Prakapavicius, D.
    Vilnius Univ, Inst Theoret Phys & Astron, Astron Observ, Sauletekio Al 3, LT-10257 Vilnius, Lithuania.
    Cayrel, R.
    PSL Res Univ, CNRS, Observ Paris, GEPI, Pl Jules Janssen, F-92195 Meudon, France.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Plez, B.
    Univ Montpellier, CNRS, LUPM, UMR 5299, F-34095 Montpellier 05, France.
    Homeier, D.
    Heidelberg Univ, Zentrum Astron, Landessternwarte, Konigstuhl 12, D-69117 Heidelberg, Germany.
    Using the CIFIST grid of (COBOLD)-B-5 3D model atmospheres to study the effects of stellar granulation on photometric colours I. Grids of 3D corrections in the UBVRI, 2MASS, HIPPARCOS, Gaia, and SDSS systems2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 611, article id A68Article in journal (Refereed)
    Abstract [en]

    Context. The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range of effective temperatures and gravities. Aims. We aim to study, in a quantitative way, the impact of granulation on colours. Methods. We use the CIFIST (Cosmological Impact of the FIrst Stars) grid of (COBOLD)-B-5 (COnservative COde for the COmputation of COmpressible COnvection in a BOx of L Dimensions, L = 2; 3) hydrodynamical models to compute emerging fluxes. These in turn are used to compute theoretical colours in the UBVRI, 2MASS, HIPPARCOS, Gaia and SDSS systems. Every (COBOLD)-B-5 model has a corresponding one dimensional (1D) plane-parallel LHD (Lagrangian HydroDynamics) model computed for the same atmospheric parameters, which we used to define a "3D correction" that can be applied to colours computed from fluxes computed from any 1D model atmosphere code. As an example, we illustrate these corrections applied to colours computed from ATLAS models. Results. The 3D corrections on colours are generally small, of the order of a few hundredths of a magnitude, yet they are far from negligible. We find that ignoring granulation effects can lead to underestimation of Te ff by up to 200 K and overestimation of gravity by up to 0.5 dex, when using colours as diagnostics. We have identified a major shortcoming in how scattering is treated in the current version of the CIFIST grid, which could lead to offsets of the order 0.01 mag, especially for colours involving blue and UV bands. We have investigated the Gaia and HIPPARCOS photometric systems and found that the (G - H-p), (BP - RP) diagram is immune to the effects of granulation. In addition, we point to the potential of the RVS photometry as a metallicity diagnostic. Conclusions. Our investigation shows that the effects of granulation should not be neglected if one wants to use colours as diagnostics of the stellar parameters of F, G, K stars. A limitation is that scattering is treated as true absorption in our current computations, thus our 3D corrections are likely an upper limit to the true effect. We are already computing the next generation of the CIFIST grid, using an approximate treatment of scattering.

  • 50. Bonifacio, P.
    et al.
    Spite, M.
    Cayrel, R.
    Hill, V.
    Spite, F.
    Francois, P.
    Plez, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ludwig, H. -G
    Caffau, E.
    Molaro, P.
    Depagne, E.
    Andersen, J.
    Barbuy, B.
    Beers, T. C.
    Nordström, B.
    Primas, F.
    First stars XII. Abundances in extremely metal-poor turnoff stars, and comparison with the giants2009In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 501, no 2, p. 519-530Article in journal (Refereed)
    Abstract [en]

    Context. The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data, however, treat giant stars that may have experienced internal mixing later. Aims. We aim to compare the results for giants with new, accurate abundances for all observable elements in 18 EMP turno. stars. Methods. VLT/UVES spectra at R similar to 45 000 and S/N similar to 130 per pixel (lambda lambda 330-1000 nm) are analysed with OSMARCS model atmospheres and the TURBOSPECTRUM code to derive abundances for C, Mg, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, and Ba. Results. For Ca, Ni, Sr, and Ba, we find excellent consistency with our earlier sample of EMP giants, at all metallicities. However, our abundances of C, Sc, Ti, Cr, Mn and Co are similar to 0.2 dex larger than in giants of similar metallicity. Mg and Si abundances are similar to 0.2 dex lower (the giant [Mg/Fe] values are slightly revised), while Zn is again similar to 0.4 dex higher than in giants of similar [Fe/H] (6 stars only). Conclusions. For C, the dwarf/giant discrepancy could possibly have an astrophysical cause, but for the other elements it must arise from shortcomings in the analysis. Approximate computations of granulation (3D) effects yield smaller corrections for giants than for dwarfs, but suggest that this is an unlikely explanation, except perhaps for C, Cr, and Mn. NLTE computations for Na and Al provide consistent abundances between dwarfs and giants, unlike the LTE results, and would be highly desirable for the other discrepant elements as well. Meanwhile, we recommend using the giant abundances as reference data for Galactic chemical evolution models.

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