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  • 1. Adamo, A.
    et al.
    Östlin, G.
    Zackrisson, E.
    Papaderos, P.
    Bergvall, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Rich, R. M.
    Micheva, G.
    Star cluster formation and evolution in Mrk 930: properties of a metal-poor starburst2011In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 415, no 3, p. 2388-2406Article in journal (Refereed)
    Abstract [en]

    We present the analysis of the large population of star clusters in the blue compact galaxy (BCG) Mrk 930. The study has been conducted by means of a photometric analysis of multiband data obtained with the Hubble Space Telescope (HST). We have reconstructed the spectral energy distributions of the star clusters and estimated the age, mass and extinction for a representative sample. Similar to previous studies of star clusters in BCGs, we observe a very young cluster population with 70 per cent of the systems formed less than 10 Myr ago. In Mrk 930, the peak in the star cluster age distribution at 4 Myr is corroborated by the presence of Wolf-Rayet spectral features, and by the observed optical and infrared (IR) line ratios [OIII]/H beta and [Ne III]/[Ne II]. The recovered extinction in these very young clusters shows large variations, with a decrease at older ages. It is likely that our analysis is limited to the optically brightest objects (i.e. systems only partially embedded in their natal cocoons; the deeply embedded clusters being undetected). We map the extinction across the galaxy using low-resolution spectra and the H alpha-to-H beta ratio, as obtained from ground-based narrow band imaging. These results are compared with the extinction distribution recovered from the clusters. We find that the mean optical extinction derived in the starburst regions is close to the averaged value observed in the clusters [more than 80 per cent of the systems have E(B - V) <= 0.2mag], but locally, do not trace the more extinguished clusters. Previous HST studies of BCGs have revealed a population of young and extremely red super star clusters. We detect a considerable fraction of clusters affected by a red excess also in Mrk 930. The nature of the red excess, which turns up at near-IR wavelengths (I band and longwards), remains unknown. We compare the cluster formation history and the star formation history, the latter derived from the fit of spectral population synthesis models to the spectra. We find a general agreement between the two independently estimated quantities. Using the cluster properties, we perform a study of the host environmental properties. We find that the cluster formation efficiency (the fraction of star formation happening in clusters) is significantly higher, suggesting a key role of the environment for the formation of these massive objects.

  • 2.
    Agarwal, Bhaskar
    et al.
    Yale Univ, Dept Astron, 52 Hillhouse Ave,Steinbach Hall, New Haven, CT 06511 USA..
    Johnson, Jarrett L.
    Los Alamos Natl Lab, Theoret Div X, Los Alamos, NM 87545 USA..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Labbe, Ivo
    Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands..
    van den Bosch, Frank C.
    Yale Univ, Dept Astron, 52 Hillhouse Ave,Steinbach Hall, New Haven, CT 06511 USA..
    Natarajan, Priyamvada
    Yale Univ, Dept Astron, 52 Hillhouse Ave,Steinbach Hall, New Haven, CT 06511 USA..
    Khochfar, Sadegh
    Univ Edinburgh, Inst Astron, Royal Observ, Edinburgh EH9 3HJ, Midlothian, Scotland..
    Detecting direct collapse black holes: making the case for CR72016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 460, no 4, p. 4003-4010Article in journal (Refereed)
    Abstract [en]

    We propose that one of the sources in the recently detected system CR7 by Sobral et al. through spectrophotometric measurements at z=6.6 harbours a direct collapse black hole (DCBH). We argue that the LW radiation field required for direct collapse in source A is provided by sources B and C.By tracing the LW production history and star formation rate over cosmic time for the halo hosting CR7 in a ACDM universe, we demonstrate that a DCBH could have formed at z similar to 20. The spectrum of source A is well fit by nebular emission from primordial gas around a BH with MBH similar to 4.4x10(6)M(circle dot) accreting at a 40 per cent of the Eddington rate, which strongly supports our interpretation of the data. Combining these lines of evidence, we argue that CR7 might well be the first DCBH candidate.

  • 3.
    Agarwal, Bhaskar
    et al.
    Heidelberg Univ, Inst Theoret Phys, Zentrum Astron, Albert Ueberle Str 2, D-69120 Heidelberg, Germany..
    Regan, John
    Heidelberg Univ, Inst Theoret Phys, Zentrum Astron, Albert Ueberle Str 2, D-69120 Heidelberg, Germany.;Dublin City Univ, Sch Math Sci, Ctr Astrophys & Relat, Dublin D09 Y5N0, Ireland..
    Klessen, Ralf S.
    Heidelberg Univ, Inst Theoret Phys, Zentrum Astron, Albert Ueberle Str 2, D-69120 Heidelberg, Germany..
    Downes, Turlough P.
    Dublin City Univ, Sch Math Sci, Ctr Astrophys & Relat, Dublin D09 Y5N0, Ireland..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala Univ, Dept Phys & Astron, Box 515, SE-75120 Uppsala, Sweden..
    An analytic resolution to the competition between Lyman-Werner radiation and metal winds in direct collapse black hole hosts2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 470, no 4, p. 4034-4038Article in journal (Refereed)
    Abstract [en]

    A near pristine atomic cooling halo close to a star forming galaxy offers a natural pathway for forming massive direct collapse black hole (DCBH) seeds, which could be the progenitors of the z > 6 redshift quasars. The close proximity of the haloes enables a sufficient Lyman-Werner flux to effectively dissociate H-2 in the core of the atomic cooling halo. A mild background may also be required to delay star formation in the atomic cooling halo, often attributed to distant background galaxies. In this paper, we investigate the impact of metal pollution from both the background galaxies and the close star forming galaxy under extremely unfavourable conditions such as instantaneous metal mixing. We find that within the time window of DCBH formation, the level of pollution never exceeds the critical threshold (Z(cr) similar to 1 x 10(-5) Z(circle dot)) and attains a maximum metallicity of Z similar to 2 x 10(- 6) Z(circle dot). As the system evolves, the metallicity eventually exceeds the critical threshold, long after the DCBH has formed.

  • 4.
    Agarwal, Jessica
    et al.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Vincent, J. -B
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hoefner, S.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Lamy, P. L.
    Aix Marseille Univ, Lab Astrophys Marseille, CNRS, UMR 7326, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France..
    Rodrigo, R.
    CSIC, Ctr Astrobiol, INTA, European Space Agcy,ESAC, POB 78, E-28691 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, 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. PAS Space Res Ctr, Poland..
    Barucci, M. A.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Cremonese, G.
    INAF Osservat Astron Padova, Vicolo Osservat 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B.
    Jet Prop Lab, M-S 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, Via Sommarive 9, I-38123 Trento, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Fornasier, S.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Fulle, M.
    INAF Osservat Astron Trieste, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gicquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Groussin, O.
    Aix Marseille Univ, LAM, CNRS, UMR 7326, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Hofmann, M.
    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. -H
    Jorda, L.
    Aix Marseille Univ, LAM, CNRS, UMR 7326, F-13388 Marseille, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, 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..
    Kueppers, M.
    ESA ESAC, POB 78, E-28691 Villanueva De La Cananda, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Naletto, G.
    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.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Shi, X.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S78-S88Article in journal (Refereed)
    Abstract [en]

    We present observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained with the narrow angle camera of the Optical, Spectroscopic, and Infrared Remote Imaging System on board the Rosetta spacecraft in 2016 January when the comet was at 2 au from the Sun outbound from perihelion. We measure the acceleration of individual aggregates through a 2 h image series. Approximately 50 per cent of the aggregates are accelerated away from the nucleus, and 50 per cent towards it, and likewise towards either horizontal direction. The accelerations are up to one order of magnitude stronger than local gravity, and are most simply explained by the combined effect of gas drag accelerating all aggregates upwards, and the recoil force from asymmetric outgassing, either from rotating aggregates with randomly oriented spin axes and sufficient thermal inertia to shift the temperature maximum away from an aggregate's subsolar region, or from aggregates with variable ice content. At least 10 per cent of the aggregates will escape the gravity field of the nucleus and feed the comet's debris trail, while others may fall back to the surface and contribute to the deposits covering parts of the Northern hemisphere. The rocket force plays a crucial role in pushing these aggregates back towards the surface. Our observations show the future back fall material in the process of ejection, and provide the first direct measurement of the acceleration of aggregates in the innermost coma (<2 km) of a comet, where gas drag is still significant.

  • 5. Alentiev, D.
    et al.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Ryabchikova, T.
    Cunha, M.
    Tsymbal, V.
    Weiss, W.
    Discovery of the longest period rapidly oscillating Ap star HD1777652012In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 421, no 1, p. L82-L86Article in journal (Refereed)
    Abstract [en]

    We present the discovery of a long-period, rapidly oscillating Ap (roAp) star, HD177765. Using high-resolution time-series observations obtained with the Ultraviolet and Visual Echelle Spectrograph at the European Southern Observatory Very Large Telescope, we found radial velocity variations with amplitudes 7-150 ms(-1) and a period of 23.6 min, exceeding that of any previously known roAp star. The largest pulsation amplitudes are observed for Eu III, Ce III and for the narrow core of H alpha. We derived the atmospheric parameters and chemical composition of HD177765, showing this star to be similar to other long-period roAp stars. Comparison with theoretical pulsational models indicates an advanced evolutionary state for HD177765. Abundance analyses of this and other roAp stars suggest a systematic variation with age of the rare-earth line anomalies seen in cool Ap stars.

  • 6.
    Alvarado-Gomez, Julian D.
    et al.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA..
    Hussain, Gaitee A. J.
    European Southern Observ, Karl Schwarzschild Str 1, D-85748 Garching, Germany.;Univ Toulouse, Inst Rech Astrophys & Planetol, UPS OMP, F-31400 Toulouse, France..
    Drake, Jeremy J.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA..
    Donati, Jean-Francois
    CNRS, IRAP, 14 Ave Edouard Belin, F-31400 Toulouse, France..
    Sanz-Forcada, Jorge
    CSIC, INTA, Ctr Astrobiol, ESAC Campus, E-28692 Madrid, Spain..
    Stelzer, Beate
    Eberhard Karls Univ Tubingen, Inst Astron & Astrophys, Sand 1, D-72076 Tubingen, Germany..
    Cohen, Ofer
    Univ Massachusetts, Dept Phys & Appl Phys, 600 Suffolk St, Lowell, MA 01854 USA..
    Amazo-Gomez, Eliana M.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.;Georg August Univ Gottingen, Inst Astrophys, Friedrich Hund Pl 1, D-37077 Gottingen, Germany..
    Grunhut, Jason H.
    Univ Toronto, Dunlap Inst Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada..
    Garraffo, Cecilia
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA..
    Moschou, Sofia P.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA..
    Silvester, James
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Oksala, Mary E.
    Univ Paris Diderot, Sorbonne Paris Cite, Univ Paris 06,LESIA, UPMC,Sorbonne Univ,CNRS,PSL Res Univ,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France.;Calif Lutheran Univ, Dept Phys, 60 West Olsen Rd 3700, Thousand Oaks, CA 91360 USA..
    Far beyond the Sun - I. The beating magnetic heart in Horologium2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 473, no 4, p. 4326-4338Article in journal (Refereed)
    Abstract [en]

    A former member of the Hyades cluster, iota Horologii (iota Hor) is a planet-hosting Sun-like star which displays the shortest coronal activity cycle known to date (P-cyc similar to 1.6 yr). With an age of similar to 625 Myr, iota Hor is also the youngest star with a detected activity cycle. The study of its magnetic properties holds the potential to provide fundamental information to understand the origin of cyclic activity and stellar magnetism in late-type stars. In this series of papers, we present the results of a comprehensive project aimed at studying the evolving magnetic field in this star and how this evolution influences its circumstellar environment. This paper summarizes the first stage of this investigation, with results from a long-term observing campaign of iota Hor using ground-based high-resolution spectropolarimetry. The analysis includes precise measurements of the magnetic activity and radial velocity of the star, and their multiple time-scales of variability. In combination with values reported in the literature, we show that the long-term chromospheric activity evolution of iota Hor follows a beating pattern, caused by the superposition of two periodic signals of similar amplitude at P-1 similar or equal to 1.97 +/- 0.02 yr and P-2 similar or equal to 1.41 +/- 0.01 yr. Additionally, using the most recent parameters for iota Hor b in combination with our activity and radial velocity measurements, we find that stellar activity dominates the radial velocity residuals, making the detection of additional planets in this system challenging. Finally, we report here the first measurements of the surface longitudinal magnetic field strength of iota Hor, which displays varying amplitudes within +/- 4G and served to estimate the rotation period of the star (P-rot = 7.70(-0.67)(+0.18) d).

  • 7.
    Amarsi, A. M.
    et al.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia..
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany..
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia..
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Collet, R.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark..
    Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 463, no 2, p. 1518-1533Article in journal (Refereed)
    Abstract [en]

    As one of the most important elements in astronomy, iron abundance determinations need to be as accurate as possible. We investigate the accuracy of spectroscopic iron abundance analyses using archetypal metal-poor stars. We perform detailed 3D non-LTE radiative transfer calculations based on 3D hydrodynamic STAGGER model atmospheres, and employ a new model atom that includes new quantum-mechanical neutral hydrogen collisional rate coefficients. With the exception of the red giant HD122563, we find that the 3D non-LTE models achieve Fe I/Fe II excitation and ionization balance as well as not having any trends with equivalent width to within modelling uncertainties of 0.05 dex, all without having to invoke any microturbulent broadening; for HD122563 we predict that the current best parallax-based surface gravity is overestimated by 0.5 dex. Using a 3D non-LTE analysis, we infer iron abundances from the 3D model atmospheres that are roughly 0.1 dex higher than corresponding abundances from 1D MARCS model atmospheres; these differences go in the same direction as the non-LTE effects themselves. We make available grids of departure coefficients, equivalent widths and abundance corrections, calculated on 1D MARCS model atmospheres and horizontally and temporally averaged 3D STAGGER model atmospheres.

  • 8.
    Asadi, Saghar
    et al.
    Stockholm Univ, Oscar Klein Ctr, Dept Astron, AlbaNova, SE-10691 Stockholm, Sweden..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Freeland, Emily
    Stockholm Univ, Oscar Klein Ctr, Dept Astron, AlbaNova, SE-10691 Stockholm, Sweden..
    Probing cold dark matter subhaloes with simulated ALMA observations of macrolensed sub-mm galaxies2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 472, no 1, p. 129-140Article in journal (Refereed)
    Abstract [en]

    If the dark matter haloes of galaxies contain large numbers of subhaloes as predicted by the Lambda cold dark matter model, these subhaloes are expected to appear in strong galaxy-galaxy lens systems as small-scale perturbations in individual images. We simulate observations of multiply lensed sub-mm galaxies at z similar to 2 as a probe of the dark matter halo of a lens galaxy at z similar to 0.5. We present detection limits for dark substructures based on a visibility plane analysis of simulated Atacama Large Millimeter/submillimeter Array (ALMA) data in bands 7, 8 and 9. We explore two effects: local surface brightness anomalies on angular scales similar to the Einstein radius and the astrometric shift of macroimages. This improves the sensitivity of our lens modelling to the mass of the lens perturber. We investigate the sensitivity of the detection of low-mass subhaloes to the projected position of the subhalo on the image plane as well as the source structure and inner density profile of the lens. We demonstrate that, using the most extended ALMA configuration, pseudo-Jaffe subhaloes can be detected with 99 per cent confidence down to M = 10(7)M(circle dot) . We show how the detection threshold for the three ALMA bands depends on the projected position of the subhalo with respect to the lensed images and conclude that, despite the highest nominal angular resolution, band 9 provides the poorest sensitivity due to observational noise. All simulations use the ALMA Full ops most extended ALMA configuration setup in CASA.

  • 9.
    Bergvall, Nils
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Zackrisson, Erik
    Caldwell, Brady
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    The red haloes of SDSS low surface brightness disc galaxies2010In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 405, no 4, p. 2697-2716Article in journal (Refereed)
    Abstract [en]

    The faint stellar haloes of galaxies contain key information about the oldest stars and the process of galaxy formation. A previous study of stacked SDSS images of disc galaxies has revealed a halo with an abnormally red r - i colour, seemingly inconsistent with our current understanding of the stellar populations inhabiting stellar haloes. Measurements of this type are, however, plagued by large uncertainties which calls for follow-up studies. Here, we investigate the statistical properties of the faint envelopes of low surface brightness disc galaxies to look for further support for a red excess. A total of 1510 nearly edge-on, bulgeless low surface brightness galaxies were selected from the SDSS Data Release 5, rescaled to the same apparent size, aligned and stacked. This procedure allows us to reach a surface brightness of mu(r) similar to 31 mag arcsec-2. After a careful assessment of instrumental light scattering effects in the stacked images, we derive median and average radial surface brightness and colour profiles in g, r and i. The sample is then divided into three subsamples according to g - r colour. All three samples exhibit a red colour excess in r - i in the thick disc/halo region. The halo colours of the full sample, g - r = 0.60 +/- 0.15 and r - i = 0.80 +/- 0.15, are found to be incompatible with the colours of any normal type of stellar population. The fact that no similar colour anomaly is seen at comparable surface brightness levels along the disc rules out a sky subtraction residual as the source of the extreme colours. A number of possible explanations for these abnormally red haloes are discussed. We find that two different scenarios - dust extinction of extragalactic background light and a stellar population with a very bottom-heavy initial mass function - appear to be broadly consistent with our observations and with similar red excesses reported in the haloes of other types of galaxies.

  • 10.
    Beth, A.
    et al.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Altwegg, K.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Balsiger, H.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Berthelier, J. -J
    Calmonte, U.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Combi, M. R.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    De Keyser, J.
    Royal Belgian Inst Space Aeron, BIRA, IASB, Ringlaan 3, B-1180 Brussels, Belgium..
    Dhooghe, F.
    Royal Belgian Inst Space Aeron, BIRA, IASB, Ringlaan 3, B-1180 Brussels, Belgium..
    Fiethe, B.
    TU Braunschweig, Inst Comp & Network Engn IDA, Hans Sommer Str 66, D-38106 Braunschweig, Germany..
    Fuselier, S. A.
    Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78228 USA.;Southwest Res Inst San Antonio, San Antonio, TX 78228 USA..
    Galand, M.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Gasc, S.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Gombosi, T. I.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    Hansen, K. C.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    Hassig, M.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78228 USA..
    Heritier, K. L.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Kopp, E.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Le Roy, L.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Mandt, K. E.
    Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78228 USA.;Southwest Res Inst San Antonio, San Antonio, TX 78228 USA..
    Peroy, S.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Rubin, M.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Semon, T.
    Univ Bern, Phys Inst, CH-3012 Bern, Switzerland..
    Tzou, C. -Y
    Vigren, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    First in situ detection of the cometary ammonium ion NH4+ (protonated ammonia NH3) in the coma of 67P/C-G near perihelion2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S562-S572Article in journal (Refereed)
    Abstract [en]

    In this paper, we report the first in situ detection of the ammonium ion NH4+ at 67P/Churyumov-Gerasimenko (67P/C-G) in a cometary coma, using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Double Focusing Mass Spectrometer (DFMS). Unlike neutral and ion spectrometers onboard previous cometary missions, the ROSINA/DFMS spectrometer, when operated in ion mode, offers the capability to distinguish NH4+ from H2O+ in a cometary coma. We present here the ion data analysis of mass-to-charge ratios 18 and 19 at high spectral resolution and compare the results with an ionospheric model to put these results into context. The model confirms that the ammonium ion NH4+ is one of the most abundant ion species, as predicted, in the coma near perihelion.

  • 11. Boyajian, T.
    et al.
    von Braun, K.
    Feiden, Gregory
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Huber, D.
    Basu, S.
    Demarque, P.
    Fischer, D. A.
    Schaefer, G.
    Mann, A. W.
    White, T. R.
    Maestro, V.
    Brewer, J.
    Lamell, C. B.
    Spada, F.
    López-Morales, M.
    Ireland, M.
    Farrington, C.
    van Belle, G. T.
    Kane, S. R.
    Jones, J.
    ten Brummelaar, T. A.
    Ciardi, D. R.
    McAlister, H. A.
    Ridgway, S.
    Goldfinger, P. J.
    Turner, N. H.
    Sturmann, L.
    Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs2015In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 447, no 1, p. 846-857Article in journal (Refereed)
    Abstract [en]

    We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be thetaLD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (Teff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R* = 0.805 +/- 0.016, 1.203 +/- 0.061 Rsun), mean stellar densities (rho* = 1.62 +/- 0.11, 0.58 +/- 0.14 rhosun), planetary radii (Rp = 1.216 +/- 0.024, 1.451 +/- 0.074 RJup), and mean planetary densities (rhop = 0.605 +/- 0.029, 0.196 +/- 0.033 rhoJup) for HD 189733 b and HD 209458 b, respectively. The stellar parameters for HD 209458, a F9 dwarf, are consistent with indirect estimates derived from spectroscopic and evolutionary modeling. However, we find that models are unable to reproduce the observational results for the K2 dwarf, HD 189733. We show that, for stellar evolutionary models to match the observed stellar properties of HD 189733, adjustments lowering the solar-calibrated mixing length parameter from 1.83 to 1.34 need to be employed.

  • 12.
    Broiles, Thomas W.
    et al.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Burch, J. L.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Chae, K.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Clark, G.
    Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA..
    Cravens, T. E.
    Univ Kansas, Dept Phys & Astron, 1450 Jayhawk Blvd, Lawrence, KS 66045 USA..
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Fuselier, S. A.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Frahm, R. A.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Gasc, S.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Goldstein, R.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Henri, P.
    CNRS, LPC2E, F-45071 Orleans, France..
    Koenders, C.
    Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Livadiotis, G.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Mandt, K. E.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Mokashi, P.
    Southwest Res Inst, Div Space Sci & Engn, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Nemeth, Z.
    Wigner Res Ctr Phys, H-1121 Budapest, Hungary..
    Odelstad, Elias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics. Univ Kansas, Dept Phys & Astron, 1450 Jayhawk Blvd, Lawrence, KS 66045 USA..
    Rubin, M.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Samara, M.
    Goddard Space Flight Ctr, Heliophys Div, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA..
    Statistical analysis of suprathermal electron drivers at 67P/Churyumov-Gerasimenko2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S312-S322Article in journal (Refereed)
    Abstract [en]

    We use observations from the Ion and Electron Sensor (IES) on board the Rosetta spacecraft to study the relationship between the cometary suprathermal electrons and the drivers that affect their density and temperature. We fit the IES electron observations with the summation of two kappa distributions, which we characterize as a dense and warm population (similar to 10 cm(-3) and similar to 16 eV) and a rarefied and hot population (similar to 0.01 cm(-3) and similar to 43 eV). The parameters of our fitting technique determine the populations' density, temperature, and invariant kappa index. We focus our analysis on the warm population to determine its origin by comparing the density and temperature with the neutral density and magnetic field strength. We find that the warm electron population is actually two separate sub-populations: electron distributions with temperatures above 8.6 eV and electron distributions with temperatures below 8.6 eV. The two sub-populations have different relationships between their density and temperature. Moreover, the two sub-populations are affected by different drivers. The hotter sub-population temperature is strongly correlated with neutral density, while the cooler sub-population is unaffected by neutral density and is only weakly correlated with magnetic field strength. We suggest that the population with temperatures above 8.6 eV is being heated by lower hybrid waves driven by counterstreaming solar wind protons and newly formed, cometary ions created in localized, dense neutral streams. To the best of our knowledge, this represents the first observations of cometary electrons heated through wave-particle interactions.

  • 13.
    Casamiquela, L.
    et al.
    Univ Barcelona, Dept Fis Quant & Astrofis, ICC IEEC, E-08007 Barcelona, Spain..
    Carrera, R.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Blanco-Cuaresma, S.
    Univ Geneva, Observ Geneve, CH-1290 Versoix, Switzerland..
    Jordi, C.
    Univ Barcelona, Dept Fis Quant & Astrofis, ICC IEEC, E-08007 Barcelona, Spain..
    Balaguer-Nunez, L.
    Univ Barcelona, Dept Fis Quant & Astrofis, ICC IEEC, E-08007 Barcelona, Spain..
    Pancino, E.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.;ASI Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy..
    Anders, F.
    Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam, Germany..
    Chiappini, C.
    Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam, Germany..
    Diaz-Perez, L.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Aguado, D. S.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Aparicio, A.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Garcia-Dias, R.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Martinez-Vazquez, C. E.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    Murabito, S.
    Inst Astrofis Canarias, E-38205 Tenerife, Spain.;Univ La Laguna, Dept Astrofis, E-38207 San Cristobal la Laguna, Spain..
    del Pino, A.
    Polish Acad Sci, Nicolaus Copernicus Astron Ctr, Ul Bartycka 18, PL-00716 Warsaw, Poland..
    OCCASO - II. Physical parameters and Fe abundances of red clump stars in 18 open clusters2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 470, no 4, p. 4363-4381Article in journal (Refereed)
    Abstract [en]

    Open clusters have long been used to study the chemodynamical evolution of the Galactic disc. This requires a homogeneously analysed sample covering a wide range of ages and distances. In this paper, we present the Open Clusters Chemical Abundances from Spanish Observatories (OCCASO) second data release. This comprises a sample of high-resolution (R > 65 000) and high signal-to-noise spectra of 115 red clump stars in 18 open clusters. We derive atmospheric parameters (T-eff, log g, xi), and [Fe/H] abundances using two analysis techniques: equivalent widths and spectral synthesis. A detailed comparison and a critical review of the results of the two methods are made. Both methods are carefully tested between them, with the Gaia FGK benchmark stars, and with an extensive sample of literature values. We perform a membership study using radial velocities and the resulting abundances. Finally, we compare our results with a chemodynamical model of the Milky Way thin disc concluding that the oldest open clusters are consistent with the models only when dynamical effects are taken into account.

  • 14.
    Casey, A. R.
    et al.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Ruchti, G.
    Lund Observ, Dept Astron & Theoret Phys, Box 43, SE-22100 Lund, Sweden..
    Masseron, T.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Randich, S.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy..
    Gilmore, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany..
    Kennedy, G. M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Koposov, S. E.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Hourihane, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Franciosini, E.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy..
    Lewis, J. R.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Magrini, L.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy..
    Morbidelli, L.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy..
    Sacco, G. G.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy..
    Worley, C. C.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Feltzing, S.
    Lund Observ, Dept Astron & Theoret Phys, Box 43, SE-22100 Lund, Sweden..
    Jeffries, R. D.
    Keele Univ, Astrophys Grp, Keele ST5 5BG, Staffs, England..
    Vallenari, A.
    Padova Observ, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Bensby, T.
    Lund Observ, Dept Astron & Theoret Phys, Box 43, SE-22100 Lund, Sweden..
    Bragaglia, A.
    Osservatorio Astron Bologna, INAF, Via Ranzani 1, I-40127 Bologna, Italy..
    Flaccomio, E.
    Osserv Astron Palermo, INAF, Piazza Parlamento 1, I-90134 Palermo, Italy..
    Francois, P.
    Univ Paris Diderot, CNRS, Observ Paris, GEPI, 5 Pl Jules Janssen, F-92190 Meudon, France..
    Korn, Andreas J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Lanzafame, A.
    Univ Catania, Sez Astrofis, Dipartimento Fis & Astron, Via S Sofia 78, I-95123 Catania, Italy..
    Pancino, E.
    Osserv Astrofis Arcetri, INAF, Largo E Fermi 5, I-50125 Florence, Italy.;ASI Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy..
    Recio-Blanco, A.
    Univ Nice Sophia Antipolis, CNRS, Observ Cote Azur, Lab Lagrange,UMR7293, CS 34229, F-06304 Nice 4, France..
    Smiljanic, R.
    Nicolaus Copernicus Astron Ctr, Dept Astrophys, Ul Rabianska 8, PL-87100 Torun, Poland..
    Carraro, G.
    European Southern Observ, Alonso Cordova 3107 Vitacura, Santiago, Chile..
    Costado, M. T.
    CSIC, Inst Astrofis Andalucia, Apdo 3004, E-18080 Granada, Spain..
    Damiani, F.
    Osserv Astron Palermo, INAF, Piazza Parlamento 1, I-90134 Palermo, Italy..
    Donati, P.
    Univ Bologna, Dipartimento Fis & Astron, Viale Berti Pichat 6-2, I-40127 Bologna, Italy..
    Frasca, A.
    Osserv Astrofis Catania, INAF, Via S Sofia 78, I-95123 Catania, Italy..
    Jofre, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England..
    Lardo, C.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England..
    de Laverny, P.
    Univ Nice Sophia Antipolis, CNRS, Observ Cote Azur, Lab Lagrange,UMR7293, CS 34229, F-06304 Nice 4, France..
    Monaco, L.
    Univ Andres Bello, Dept Ciencias Fis, Republ 220, Santiago, Chile..
    Prisinzano, L.
    Osserv Astron Palermo, INAF, Piazza Parlamento 1, I-90134 Palermo, Italy..
    Sbordone, L.
    Millennium Inst Astrophys, Av Vicuna Mackenna 4860, Santiago 7820436, Chile.;Pontificia Univ Catolica Chile, Av Vicuna Mackenna 4860, Santiago 7820436, Chile..
    Sousa, S. G.
    Univ Porto, CAUP, Inst Astrofis & Ciencias Espaco, Rua Estrelas, P-4150762 Oporto, Portugal..
    Tautvaisiene, G.
    Vilnius Univ, Inst Theoret Phys & Astron, A Gostauto 12, LT-01108 Vilnius, Lithuania..
    Zaggia, S.
    Padova Observ, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Zwitter, T.
    Univ Ljubljana, Fac Math & Phys, Jadranska 19, Ljubljana 1000, Slovenia..
    Delgado Mena, E.
    Univ Porto, CAUP, Inst Astrofis & Ciencias Espaco, Rua Estrelas, P-4150762 Oporto, Portugal..
    Chorniy, Y.
    Vilnius Univ, Inst Theoret Phys & Astron, A Gostauto 12, LT-01108 Vilnius, Lithuania..
    Martell, S. L.
    Univ New South Wales, Sch Phys, Sydney, NSW 2052, Australia..
    Aguirre, V. Silva
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark..
    Miglio, A.
    Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England..
    Chiappini, C.
    Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam, Germany..
    Montalban, J.
    Univ Padua, Dept Phys & Astron G Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Morel, T.
    Univ Liege, Inst Astrophys & Geophys, Quartier Agora, Bat B5c,Allee 6 Aout 19c, B-4000 Liege, Belgium..
    Valentini, M.
    Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam, Germany..
    The Gaia-ESO Survey: revisiting the Li-rich giant problem2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 461, no 3, p. 3336-3352Article in journal (Refereed)
    Abstract [en]

    The discovery of lithium-rich giants contradicts expectations from canonical stellar evolution. Here we report on the serendipitous discovery of 20 Li-rich giants observed during the Gaia-ESO Survey, which includes the first nine Li-rich giant stars known towards the CoRoT fields. Most of our Li-rich giants have near-solar metallicities and stellar parameters consistent with being before the luminosity bump. This is difficult to reconcile with deep mixing models proposed to explain lithium enrichment, because these models can only operate at later evolutionary stages: at or past the luminosity bump. In an effort to shed light on the Li-rich phenomenon, we highlight recent evidence of the tidal destruction of close-in hot Jupiters at the sub-giant phase. We note that when coupled with models of planet accretion, the observed destruction of hot Jupiters actually predicts the existence of Li-rich giant stars, and suggests that Li-rich stars should be found early on the giant branch and occur more frequently with increasing metallicity. A comprehensive review of all known Li-rich giant stars reveals that this scenario is consistent with the data. However, more evolved or metal-poor stars are less likely to host close-in giant planets, implying that their Li-rich origin requires an alternative explanation, likely related to mixing scenarios rather than external phenomena.

  • 15. Cruzalebes, P.
    et al.
    Jorissen, A.
    Rabbia, Y.
    Chiavassa, A.
    Paladini, C.
    Sacuto, Stéphane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Siopis, C.
    Sadowski, G.
    Spang, A.
    Chesneau, O.
    Measuring deviation from centrosymmetry for a source brightness distribution observed by spectro-interferometry2014In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 443, no 4, p. 3550-3563Article in journal (Refereed)
    Abstract [en]

    We report on the testing of the centrosymmetry parameter (CSP), an indicator of deviation from centrosymmetry of a source brightness distribution. This indicator is derived from the spectral distribution of the triple product measured over three baselines of an optical interferometer. Numerical simulations using parametric toy-models (separated or transiting binary, one-spot model), generated with the SPIDAST software, are applied to the VLTI/AMBER facility in the K band (2.2 mu m). The simulations show that, in case of centrosymmetry, the CSP parameter is in agreement with the usual phase of the spectral mean of the triple product (called GCP, global closure phase). To justify the preferential use of CSP rather than GCP, we show situations with asymmetric geometries for which GCP diagnoses centrosymmetry, while CSP does not. Using realistic Roche lobe-filling binary and hydrodynamic convective models, we show that CSP can also be used as an indicator for geometric similarity between physical and toy-models. Thus, dealing with real data, the toy-model parameters can be fitted on the measured CSP values, in order to assess the input-parameter values of the most suitable complex physical model that will be used to interpret the data.

  • 16. Cruzalebes, P.
    et al.
    Jorissen, A.
    Rabbia, Y.
    Sacuto, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Chiavassa, A.
    Pasquato, E.
    Plez, B.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Spang, A.
    Chesneau, O.
    Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER(star)2013In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 434, no 1, p. 437-450Article in journal (Refereed)
    Abstract [en]

    Thanks to their large angular dimension and brightness, red giants and supergiants are privileged targets for optical long-baseline interferometers. 16 red giants and supergiants have been observed with the VLTI/AMBER facility over a 2-year period, at medium spectral resolution (R = 1500) in the K band. The limb-darkened angular diameters are derived from fits of stellar atmospheric models on the visibility and the triple product data. The angular diameters do not show any significant temporal variation, except for one target: TX Psc, which shows a variation of 4 per cent using visibility data. For the eight targets previously measured by long-baseline interferometry (LBI) in the same spectral range, the difference between our diameters and the literature values is less than 5 per cent, except for TX Psc, which shows a difference of 11 per cent. For the eight other targets, the present angular diameters are the first measured from LBI. Angular diameters are then used to determine several fundamental stellar parameters, and to locate these targets in the Hertzsprung-Russell diagram (HRD). Except for the enigmatic Tc-poor low-mass carbon star W Ori, the location of Tc-rich stars in the HRD matches remarkably well the thermally-pulsating asymptotic giant branch, as it is predicted by the stellar evolution models. For pulsating stars with periods available, we compute the pulsation constant and locate the stars along the various sequences in the period-luminosity diagram. We confirm the increase in mass along the pulsation sequences, as predicted by theory, except for W Ori which, despite being less massive, appears to have a longer period than T Cet along the first-overtone sequence.

  • 17. Cruzalebes, P.
    et al.
    Rabbia, Y.
    Jorissen, A.
    Spang, A.
    Sacuto, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, The Uppsala Astronomical Observatory.
    Pasquato, E.
    Chiavassa, A.
    Chesneau, O.
    Freville, P.
    SPIDAST: a new modular software to process spectrointerferometric measurements2013In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 432, no 2, p. 1658-1671Article in journal (Refereed)
    Abstract [en]

    Extracting stellar fundamental parameters from Spectrointerferometric (SPI) data requires reliable estimates of observables and with robust uncertainties (visibility, triple product, phase closure). A number of fine calibration procedures are necessary throughout the reduction process. Testing departures from centrosymmetry of brightness distributions is a useful complement. Developing a set of automatic routines called spidast (made available to the community) to reduce, calibrate and interpret raw data sets of instantaneous spectrointerferograms at the spectral channel level, we complement (and in some respects improve) the ones contained in the amdlib Data Reduction Software. Our new software spidast is designed to work in an automatic mode, free from subjective choices, while being versatile enough to suit various processing strategies. spidast performs the following automated operations: weighting of non-aberrant SPI data (visibility, triple product), fine spectral calibration (subpixel level), accurate and robust determinations of stellar diameters for calibrator sources (and their uncertainties as well), correction for the degradations of the interferometer response in visibility and triple product, calculation of the centrosymmetry parameter from the calibrated triple product, fit of parametric chromatic models on SPI observables, to extract model parameters. spidast is currently applied to the scientific study of 18 cool giant and supergiant stars, observed with the VLTI/AMBER facility at medium resolution in the K band. Because part of their calibrators have no diameter in the current catalogues, spidast provides new determinations of the angular diameters of all calibrators. Comparison of spidast final calibrated observables with amdlib determinations shows good agreement, under good and poor seeing conditions.

  • 18. De Silva, G. M.
    et al.
    Freeman, K. C.
    Bland-Hawthorn, J.
    Martell, S.
    de Boer, E. Wylie
    Asplund, M.
    Keller, S.
    Sharma, S.
    Zucker, D. B.
    Zwitter, T.
    Anguiano, B.
    Bacigalupo, C.
    Bayliss, D.
    Beavis, M. A.
    Bergemann, M.
    Campbell, S.
    Cannon, R.
    Carollo, D.
    Casagrande, L.
    Casey, A. R.
    Da Costa, G.
    D'Orazi, V.
    Dotter, A.
    Duong, L.
    Heger, A.
    Ireland, M. J.
    Kafle, P. R.
    Kos, J.
    Lattanzio, J.
    Lewis, G. F.
    Lin, J.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Munari, U.
    Nataf, D. M.
    O'Toole, S.
    Parker, Q.
    Reid, W.
    Schlesinger, K. J.
    Sheinis, A.
    Simpson, J. D.
    Stello, D.
    Ting, Y. -S
    Traven, G.
    Watson, F.
    Wittenmyer, R.
    Yong, D.
    Zerjal, M.
    The GALAH survey: scientific motivation2015In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 449, no 3, p. 2604-2617Article in journal (Refereed)
    Abstract [en]

    The Galactic Archaeology with HERMES (GALAH) survey is a large high-resolution spectroscopic survey using the newly commissioned High Efficiency and Resolution Multi-Element Spectrograph (HERMES) on the Anglo-Australian Telescope. The HERMES spectrograph provides high-resolution (R similar to 28 000) spectra in four passbands for 392 stars simultaneously over a 2 deg field of view. The goal of the survey is to unravel the formation and evolutionary history of the Milky Way, using fossil remnants of ancient star formation events which have been disrupted and are now dispersed throughout the Galaxy. Chemical tagging seeks to identify such dispersed remnants solely from their common and unique chemical signatures; these groups are unidentifiable from their spatial, photometric or kinematic properties. To carry out chemical tagging, the GALAH survey will acquire spectra for a million stars down to V similar to 14. The HERMES spectra of FGK stars contain absorption lines from 29 elements including light proton-capture elements, alpha-elements, odd-Z elements, iron-peak elements and n-capture elements from the light and heavy s-process and the r-process. This paper describes the motivation and planned execution of the GALAH survey, and presents some results on the first-light performance of HERMES.

  • 19. de Val-Borro, M.
    et al.
    Edgar, R. G.
    Artymowicz, P.
    Ciecielag, P.
    Cresswell, P.
    D'Angelo, G.
    Delgado-Donate, E. J.
    Dirksen, G.
    Fromang, S.
    Gawryszczak, A.
    Klahr, H.
    Kley, W.
    Lyra, Wladimir
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, The Uppsala Astronomical Observatory.
    Masset, F.
    Mellema, G.
    Nelson, R. P.
    Paardekooper, S. -J
    Peplinski, A.
    Pierens, A.
    Plewa, T.
    Rice, K.
    Schaefer, C.
    Speith, R.
    A comparative study of disc-planet interaction2006In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 370, no 2, p. 529-558Article in journal (Refereed)
    Abstract [en]

    We perform numerical simulations of a disc-planet system using various grid-based and smoothed particle hydrodynamics (SPH) codes. The tests are run for a simple setup where Jupiter and Neptune mass planets on a circular orbit open a gap in a protoplanetary disc during a few hundred orbital periods. We compare the surface density contours, potential vorticity and smoothed radial profiles at several times. The disc mass and gravitational torque time evolution are analysed with high temporal resolution. There is overall consistency between the codes. The density profiles agree within about 5 per cent for the Eulerian simulations. The SPH results predict the correct shape of the gap although have less resolution in the low-density regions and weaker planetary wakes. The disc masses after 200 orbital periods agree within 10 per cent. The spread is larger in the tidal torques acting on the planet which agree within a factor of 2 at the end of the simulation. In the Neptune case, the dispersion in the torques is greater than for Jupiter, possibly owing to the contribution from the not completely cleared region close to the planet.

  • 20. de Val-Borro, M.
    et al.
    Gahm, G. F.
    Stempels, Henricus C.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Peplinski, A.
    Modelling circumbinary gas flows in close T Tauri binaries star2011In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 413, no 4, p. 2679-2688Article in journal (Refereed)
    Abstract [en]

    Young close binaries open central gaps in the surrounding circumbinary accretion disc, but the stellar components may still gain mass from gas crossing through the gap. It is not well understood how this process operates and how the stellar components are affected by such inflows. Our main goal is to investigate how gas accretion takes place and evolves in close T Tauri binary systems. In particular, we model the accretion flows around two close T Tauri binaries, V4046 Sgr and DQ Tau, both showing periodic changes in emission lines, although their orbital characteristics are very different. In order to derive the density and velocity maps of the circumbinary material, we employ two-dimensional hydrodynamic simulations with a locally isothermal equation of state. The flow patterns become quasi-stable after a few orbits in the frame corotating with the system. Gas flows across the circumbinary gap through the corotating Lagrangian points, and local circumstellar discs develop around both components. Spiral density patterns develop in the circumbinary disc that transport angular momentum efficiently. Mass is preferentially channelled towards the primary and its circumstellar disc is more massive than the disc around the secondary. We also compare the derived density distribution to observed line profile variability. The line profile variability tracing the gas flows in the central cavity shows clear similarities with the corresponding observed line profile variability in V4046 Sgr, but only when the local circumstellar disc emission was excluded. Closer to the stars normal magnetospheric accretion may dominate, while further out the dynamic accretion process outlined here dominates. Periodic changes in the accretion rates on to the stars can explain the outbursts of line emission observed in eccentric systems such as DQ Tau.

  • 21.
    Deshapriya, J. D. P.
    et al.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Barucci, M. A.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Fornasier, S.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Feller, C.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Hasselmann, P. H.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    El-Maarry, M. R.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Pajola, M.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P. L.
    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, E-28850 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, 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. PAS Space Reserch Ctr, Poland.
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Cremonese, G.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B. J. R.
    JPL, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Debei, S.
    Univ Padua, Dept Mech Engn, Via Venezia 1, I-35131 Padua, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    De Cecco, M.
    Univ Trento, UNITN, Via Mesiano 77, I-38100 Trento, Italy..
    Fulle, M.
    INAF, Osservatorio Astron Trieste, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gicquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Groussin, O.
    CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hofmann, M.
    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, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kramm, R.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kueppers, M.
    ESA, ESAC, POB 78, E-28691 Villanueva De La Canada, Spain..
    Lara, L.
    CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Mottola, S.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Naletto, G.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, Via Gradenigo 6, I-35131 Padua, Italy.;Univ Padua, Ctr Studies & Act Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Perna, D.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Pommerol, A.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Spectrophotometry of the Khonsu region on the comet 67P/Churyumov-Gerasimenko using OSIRIS instrument images2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S274-S286Article in journal (Refereed)
    Abstract [en]

    Our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the Khonsu region on the comet 67P/Churyumov-Gerasimenko. Despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. It is noticeable that the smooth areas in Khonsu possess similar spectrophotometric behaviour to some other regions of the comet. We observed bright patches on Khonsu with an estimation of >40 per cent of normal albedo and suggest that they are associated with H2O ice. One of the studied bright patches has been observed to exist on the surface for more than 5 months without a major decay of its size, implying the existence of potential sub-surface icy layers. Its location may be correlated with a cometary outburst during the perihelion passage of the comet in 2015 August, and we interpret it to have triggered the surface modifications necessary to unearth the stratified icy layers beneath the surface. A boulder analysis on Khonsu leads to a power-law index of -3.1 + 0.2/-0.3 suggesting a boulder formation, shaped by varying geological processes for different morphological units.

  • 22. Distefano, E.
    et al.
    Lanzafame, A. C.
    Lanza, A. F.
    Messina, S.
    Korn, Andreas J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Cuypers, J.
    Determination of rotation periods in solar-like stars with irregular sampling: the Gaia case2012In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 421, no 4, p. 2774-2785Article in journal (Refereed)
    Abstract [en]

    We present a study on the determination of rotation periods (P) of solar-like stars from the photometric irregular time sampling of the European Space Agency Gaia mission, currently scheduled for launch in 2013, taking into account its dependence on ecliptic coordinates. We examine the case of solar twins as well as thousands of synthetic time series of solar-like stars rotating faster than the Sun. In the case of solar twins, we assume that the Gaia unfiltered photometric passband G will mimic the variability of the total solar irradiance as measured by the Variability of solar IRradiance and Gravity Oscillations (VIRGO) experiment. For stars rotating faster than the Sun, light curves are simulated using synthetic spectra for the quiet atmosphere, the spots and the faculae combined by applying semi-empirical relationships relating the level of photospheric magnetic activity to the stellar rotation and the Gaia instrumental response. The capabilities of the Deeming, LombScargle and phase dispersion minimization methods in recovering the correct rotation periods are tested and compared. The false alarm probability is computed using Monte Carlo simulations and compared with analytical formulae. The Gaia scanning law makes the rate of correct detection of rotation periods strongly dependent on the ecliptic latitude (beta). We find that for P? 1 d, the rate of correct detection increases with beta from 2030 per cent at beta? 0 to a peak of 70 per cent at beta= 45 degrees; then it abruptly falls below 10 per cent at beta > 45 degrees. For P > 5 d, the rate of correct detection is quite low and for solar twins is only 5 per cent on average.

  • 23.
    Doughty, Caitlin
    et al.
    New Mexico State Univ, Dept Astron, Las Cruces, NM 88001 USA..
    Finlator, Kristian
    New Mexico State Univ, Dept Astron, Las Cruces, NM 88001 USA..
    Oppenheimer, Benjamin D.
    Univ Colorado, Dept Astrophys & Planetary Sci, CASA, 389-UCB, Boulder, CO 80309 USA..
    Dave, Romeel
    Royal Observ, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland.;Univ Western Cape, Dept Phys & Astron, ZA-7535 Cape Town, South Africa..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Aligned metal absorbers and the ultraviolet background at the end of reionization2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 475, no 4, p. 4717-4727Article in journal (Refereed)
    Abstract [en]

    We use observations of spatially aligned C II, C IV, Si II, Si IV, and O I absorbers to probe the slope and intensity of the ultraviolet background (UVB) at z similar to 6. We accomplish this by comparing observations with predictions from a cosmological hydrodynamic simulation using three trial UVBs applied in post-processing: a spectrally soft, fluctuating UVB calculated using multifrequency radiative transfer; a soft, spatially uniform UVB; and a hard, spatially uniform 'quasars-only' model. When considering our paired high-ionization absorbers (C IV/Si IV), the observed statistics strongly prefer the hard, spatially uniform UVB. This echoes recent findings that cosmological simulations generically underproduce strong C IV absorbers at z > 5. A single low/high ionization pair (Si II/Si IV), by contrast, shows a preference for the HM12 UVB, whereas two more (C II/C IV and O I/C IV) show no preference for any of the three UVBs. Despite this, future observations of specific absorbers, particularly Si IV/C IV, with next-generation telescopes probing to lower column densities should yield tighter constraints on the UVB.

  • 24.
    Duong, L.
    et al.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Freeman, K. C.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Casagrande, L.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Buder, S.
    Max Planck Inst Astron, Koenigstuhl 17, D-69117 Heidelberg, Germany.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. Max Planck Inst Astron, Heidelberg, Germany.
    Ness, M.
    Max Planck Inst Astron, Koenigstuhl 17, D-69117 Heidelberg, Germany.
    Bland-Hawthorn, J.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia.
    De Silva, G. M.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia;Australian Astron Observ, N Ryde, NSW 1670, Australia.
    D'Orazi, V.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Kos, J.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia.
    Lewis, G. F.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia.
    Lin, J.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Martell, S. L.
    Univ New South Wales, Sch Phys, Sydney, NSW 2052, Australia.
    Schlesinger, K.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Sharma, S.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia.
    Simpson, J. D.
    Australian Astron Observ, N Ryde, NSW 1670, Australia.
    Zucker, D. B.
    Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia.
    Zwitter, T.
    Univ Ljubljana, Fac Math & Phys, Jadranska 19, Ljubljana 1000, Slovenia.
    Anguiano, B.
    Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia;Univ Virginia, Dept Astron, POB 400325, Charlottesville, VA 22904 USA.
    Da Costa, G. S.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia.
    Hyde, E.
    Western Sydney Univ, Locked Bag 1797, Penrith, NSW 1797, Australia.
    Horner, J.
    Univ Southern Queensland, Toowoomba, Qld 4350, Australia.
    Kafle, P. R.
    Univ Western Australia, ICRAR, 35 Stirling Highway, Crawley, WA 6009, Australia.
    Nataf, D. M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia;Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA;Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA.
    Reid, W.
    Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia;Western Sydney Univ, Locked Bag 1797, Penrith, NSW 2751, Australia;Aarhus Univ, Stellar Astrophys Ctr, Dept Phys & Astron, DK-8000 Aarhus C, Denmark.
    Stello, D.
    Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia;Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia;Inst Adv Study, Olden Lane, Princeton, NJ 08540 USA.
    Ting, Y. -S
    Wyse, R. F. G.
    Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA;Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA.
    The GALAH survey: properties of the Galactic disc(s) in the solar neighbourhood2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 476, no 4, p. 5216-5232Article in journal (Refereed)
    Abstract [en]

    Using data from the GALAH pilot survey, we determine properties of the Galactic thin and thick discs near the solar neighbourhood. The data cover a small range of Galactocentric radius (7.9 less than or similar to R-GC less than or similar to 9.5 kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude 260 degrees <= l <= 280 degrees). This allows us to reliably measure the vertical density and abundance profiles of the chemically and kinematically defined 'thick' and 'thin' discs of the Galaxy. The thin disc (low-alpha population) exhibits a steep negative vertical metallicity gradient, at d[M/H]/dz = -0.18 +/- 0.01 dex kpc(-1), which is broadly consistent with previous studies. In contrast, its vertical alpha-abundance profile is almost flat, with a gradient of d[alpha/M]/dz = 0.008 +/- 0.002 dex kpc(-1). The steep vertical metallicity gradient of the low-a population is in agreement with models where radial migration has a major role in the evolution of the thin disc. The thick disc (high-alpha population) has a weaker vertical metallicity gradient d[M/H]/dz = -0.058 +/- 0.003 dex kpc(-1). The aabundance of the thick disc is nearly constant with height, d[alpha/M]/dz = 0.007 +/- 0.002 dex kpc(-1). The negative gradient in metallicity and the small gradient in [alpha/M] indicate that the high-alpha population experienced a settling phase, but also formed prior to the onset of major Type I alpha supernova enrichment. We explore the implications of the distinct alpha-enrichments and narrow [alpha/M] range of the sub-populations in the context of thick disc formation.

  • 25.
    Edberg, Niklas J. T.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Alho, M.
    Aalto Univ, Sch Elect Engn, Dept Radio Sci & Engn, POB 13000, FI-00076 Aalto, Finland..
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Andrews, David J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Behar, E.
    Swedish Inst Space Phys, Box 812, SE-98128 Kiruna, Sweden..
    Burch, J. L.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Carr, C. M.
    Imperial Coll London, Exhibit Rd, London SW7 2AZ, England..
    Cupido, E.
    Imperial Coll London, Exhibit Rd, London SW7 2AZ, England..
    Engelhardt, Ilka. A. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Eriksson, Anders I.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Glassmeier, K. -H
    Goetz, C.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Goldstein, R.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Henri, P.
    Lab Phys & Chim Environm & Espace, F-45071 Orleans 2, France..
    Johansson, Fredrik L.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Koenders, C.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Mandt, K.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78238 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Moestl, C.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria..
    Nilsson, H.
    Swedish Inst Space Phys, Box 812, SE-98128 Kiruna, Sweden..
    Odelstad, Elias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Richter, I.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Wedlund, C. Simon
    Univ Oslo, Dept Phys, Box 1048 Blindern, N-0316 Oslo, Norway..
    Wieser, G. Stenberg
    Swedish Inst Space Phys, Box 812, SE-98128 Kiruna, Sweden..
    Szego, K.
    Wigner Res Ctr Phys, Konkoly Thege Miklos Ut 29-33, H-1121 Budapest, Hungary..
    Vigren, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Volwerk, M.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria..
    CME impact on comet 67P/Churyumov-Gerasimenko2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S45-S56Article in journal (Refereed)
    Abstract [en]

    We present Rosetta observations from comet 67P/Churyumov-Gerasimenko during the impact of a coronal mass ejection (CME). The CME impacted on 2015 Oct 5-6, when Rosetta was about 800 km from the comet nucleus, and 1.4 au from the Sun. Upon impact, the plasma environment is compressed to the level that solar wind ions, not seen a few days earlier when at 1500 km, now reach Rosetta. In response to the compression, the flux of suprathermal electrons increases by a factor of 5-10 and the background magnetic field strength increases by a factor of similar to 2.5. The plasma density increases by a factor of 10 and reaches 600 cm(-3), due to increased particle impact ionization, charge exchange and the adiabatic compression of the plasma environment. We also observe unprecedentedly large magnetic field spikes at 800 km, reaching above 200 nT, which are interpreted as magnetic flux ropes. We suggest that these could possibly be formed by magnetic reconnection processes in the coma as the magnetic field across the CME changes polarity, or as a consequence of strong shears causing Kelvin-Helmholtz instabilities in the plasma flow. Due to the limited orbit of Rosetta, we are not able to observe if a tail disconnection occurs during the CME impact, which could be expected based on previous remote observations of other CME-comet interactions.

  • 26.
    Engelhardt, Ilka. A. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Stenberg Wieser, G.
    Goetz, C.
    Rubin, M.
    Henri, P.
    Nilsson, H.
    Odelstad, Elias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics.
    Hajra, R.
    Valliéres, X.
    Plasma Density Structures at Comet 67P/Churyumov-Gerasimenko2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 477, no 1, p. 1296-1307Article in journal (Refereed)
    Abstract [en]

    We present Rosetta RPC case study from four events at various radial distance, phase angle and local time from autumn 2015, just after perihelion of comet 67P/Churyumov-Gerasimenko. Pulse like (high amplitude, up to minutes in time) signatures are seen with several RPC instruments in the plasma density (LAP, MIP), ion energy and flux (ICA) as well as magnetic field intensity (MAG). Furthermore the cometocentric distance relative to the electron exobase is seen to be a good organizing parameter for the measured plasma variations. The closer Rosetta is to this boundary, the more pulses are measured. This is consistent with the pulses being filaments of plasma originating from the diamagnetic cavity boundary as predicted by simulations. 

  • 27.
    Farihi, J.
    et al.
    UCL, Dept Phys & Astron, London WC1E 6BT, England..
    Fossati, L.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Wheatley, P. J.
    Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England..
    Metzger, B. D.
    Columbia Univ, Dept Phys, 538 W 120th St, New York, NY 10027 USA..
    Mauerhan, J.
    Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA..
    Bachman, S.
    Indiana Univ Penn, Dept Phys, Indiana, PA 15705 USA.;Wesleyan Univ, Astron Dept, Middletown, CT 06459 USA.;Wesleyan Univ, Van Vleck Observ, Middletown, CT 06459 USA..
    Gänsicke, B. T.
    Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England..
    Redfield, S.
    Wesleyan Univ, Astron Dept, Middletown, CT 06459 USA.;Wesleyan Univ, Van Vleck Observ, Middletown, CT 06459 USA..
    Cauley, P. W.
    Wesleyan Univ, Astron Dept, Middletown, CT 06459 USA.;Wesleyan Univ, Van Vleck Observ, Middletown, CT 06459 USA..
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Achilleos, N.
    UCL, Dept Phys & Astron, London WC1E 6BT, England..
    Stone, N.
    Columbia Univ, Dept Astron, New York, NY 10027 USA..
    Magnetism, X-rays and accretion rates in WD 1145+017 and other polluted white dwarf systems2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 474, no 1, p. 947-960Article in journal (Refereed)
    Abstract [en]

    This paper reports circular spectropolarimetry and X-ray observations of several polluted white dwarfs including WD 1145+017, with the aim to constrain the behaviour of disc material and instantaneous accretion rates in these evolved planetary systems. Two stars with previously observed Zeeman splitting, WD 0322-019 and WD 2105-820, are detected above 5 sigma and < B-z > > 1 kG, while WD 1145+017, WD 1929+011, and WD 2326+049 yield (null) detections below this minimum level of confidence. For these latter three stars, high-resolution spectra and atmospheric modelling are used to obtain limits on magnetic field strengths via the absence of Zeeman splitting, finding B-* < 20 kG based on data with resolving power R approximate to 40 000. An analytical framework is presented for bulk Earth composition material falling on to the magnetic polar regions of white dwarfs, where X-rays and cyclotron radiation may contribute to accretion luminosity. This analysis is applied to X-ray data for WD 1145+017, WD 1729+371, and WD 2326+049, and the upper bound count rates are modelled with spectra for a range of plasma kT = 1-10 keV in both the magnetic and non-magnetic accretion regimes. The results for all three stars are consistent with a typical dusty white dwarf in a steady state at 108-109 g s(-1). In particular, the non-magnetic limits for WD 1145+017 are found to be well below previous estimates of up to 10(12) g s(-1), and likely below 1010 g s(-1), thus suggesting the star-disc system may be average in its evolutionary state, and only special in viewing geometry.

  • 28.
    Feller, C.
    et al.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Fornasier, S.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Hasselmann, P. H.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Barucci, A.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Preusker, F.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Scholten, F.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, 38 Rue Freder Joliot Curie, F-13388 Marseille, France..
    Pommerol, A.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Jost, B.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Poch, O.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    ElMaary, M. R.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Belskaya, I.
    Kharkov Natl Univ, Inst Astron, Sumska Str 35, UA-61022 Kharkov, Ukraine..
    Pajola, M.
    NASA, Ames Res Ctr, Moett Field, CA 94035 USA.;Univ Padua, Ctr Studies & Activ Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P. L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, 38 Rue Freder Joliot Curie, F-13388 Marseille, France..
    Koschny, D.
    ESA, European Space Res & Technol Ctr, Res & Sci Support Off, Keplerlaan 1,Postbus 299, NL-2201 AZ Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Poland..
    Rodrigo, R.
    CSIC, European Space Agcy, ESAC, Ctr Astrobiol,INTA, POB 78, Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Agarwal, J.
    A'Hearn, M.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Ctr Studies & Activ Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Cremonese, G.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR, IFN, UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B. J. R.
    Jet Prop Lab, M-S 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, Via Mesiano 77, I-38100 Trento, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Fulle, M.
    INAF, Osservatorio Astron, Via Tiepolo 11, I-34014 Trieste, Italy..
    Giquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, 38 Rue Freder Joliot Curie, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, C Glorieta Astron S-N, E-18008 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hofmann, M.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Keller, H.
    Tech Univ Carolo Wilhelmina Braunschweig, IGEP, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Ip, W. -H
    Knollenberg, J.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kovacs, G.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Kramm, J. -R
    Kuehrt, E.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    ESAC, ESA, POB 78, E-28691 Madrid, Spain..
    Lara, M. L.
    Lazzarin, M.
    Leyrat, C.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Moreno, J. J. Lopez
    Tech Univ Carolo Wilhelmina Braunschweig, IGEP, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Marzari, F.
    Masoumzadeh, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Mottola, S.
    Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planeten Forsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Naletto, G.
    Univ Padua, Ctr Studies & Activ Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy.;CNR, IFN, UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Perna, D.
    Sorbonne Univ, UPMC Univ Paris 06, Univ Paris Diderot,CNRS, PSL Res Univ,LESIA,Observ Paris,Sorbanne Paris Ci, 5 Pl J Janssen, F-92195 Meudon, France..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Shi, X.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Decimetre-scaled spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S287-S303Article in journal (Refereed)
    Abstract [en]

    We present the results of the photometric and spectrophotometric properties of the 67P/Churyumov-Gerasimenko nucleus derived with the Optical, Spectroscopic and Infrared Remote Imaging System instrument during the closest fly-by over the comet, which took place on 2015 February 14 at a distance of similar to 6 km from the surface. Several images covering the 0 degrees-33 degrees. phase angle range were acquired, and the spatial resolution achieved was 11 cm pixel(-1). The flown-by region is located on the big lobe of the comet, near the borders of the Ash, Apis and Imhotep regions. Our analysis shows that this region features local heterogeneities at the decimetre scale. We observed difference of reflectance up to 40 per cent between bright spots and sombre regions, and spectral slope variations up to 50 per cent. The spectral reddening effect observed globally on the comet surface by Fornasier et al. (2015) is also observed locally on this region, but with a less steep behaviour. We note that numerous metre-sized boulders, which exhibit a smaller opposition effect, also appear spectrally redder than their surroundings. In this region, we found no evidence linking observed bright spots to exposed water-ice-rich material. We fitted our data set using the Hapke 2008 photometric model. The region overflown is globally as dark as the whole nucleus (geometric albedo of 6.8 per cent) and it has a high porosity value in the uppermost layers (86 per cent). These results of the photometric analysis at a decimetre scale indicate that the photometric properties of the flown-by region are similar to those previously found for the whole nucleus.

  • 29.
    Finlator, Kristian
    et al.
    New Mexico State Univ, MSC 4500, Las Cruces, NM 88003 USA.;Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark..
    Oppenheimer, B. D.
    Univ Colorado, Dept Astrophys & Planetary Sci, CASA, 389 UCB, Boulder, CO 80309 USA..
    Dave, Romeel
    Univ Western Cape, ZA-7535 Cape Town, South Africa.;South African Astron Observ, ZA-7525 Cape Town, South Africa.;African Inst Math Sci, ZA-7545 Cape Town, South Africa..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Thompson, Robert
    Univ Illinois, NCSA, Urbana, IL 61820 USA..
    Huang, Shuiyao
    Univ Massachussetts, Dept Astron, Amherst, MA 01003 USA..
    The soft, fluctuating UVB at z similar to 6 as traced by C IV, Si IV, and C II2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 459, no 3, p. 2299-2310Article in journal (Refereed)
    Abstract [en]

    The sources that drove cosmological reionization left clues regarding their identity in the slope and inhomogeneity of the ultraviolet ionizing background (UVB): bright quasars (QSOs) generate a hardUVBwith predominantly large-scale fluctuations while Population II stars generate a softer one with smaller scale fluctuations. Metal absorbers probe the UVB's slope because different ions are sensitive to different energies. Likewise, they probe spatial fluctuations because they originate in regions where a galaxy-driven UVB is harder and more intense. We take a first step towards studying the reionization-epoch UVB's slope and inhomogeneity by comparing observations of 12 metal absorbers at z similar to 6 versus predictions from a cosmological hydrodynamic simulation using three different UVBs: a soft, spatially inhomogeneous ' galaxies+QSOs' UVB; a homogeneous 'galaxies+QSOs' UVB, and a 'QSOs-only' model. All UVBs reproduce the observed column density distributions of CII, Si IV, and CIV reasonably well although high-column, high-ionization absorbers are underproduced, reflecting numerical limitations. With upper limits treated as detections, only a soft, fluctuating UVB reproduces both the observed Si IV/CIV and CII/CIV distributions. The QSOs-only UVB overpredicts both CIV/CII and CIV/Si IV, indicating that it is too hard. The Haardt & Madau (2012) UVB underpredicts CIV/Si IV, suggesting that it lacks amplifications near galaxies. Hence current observations prefer a soft, fluctuating UVB as expected from a predominantly Population II background although they cannot rule out a harder one. Future observations probing a factor of 2 deeper in metal column density will distinguish between the soft, fluctuating and QSOs-only UVBs.

  • 30.
    Finlator, Kristian
    et al.
    New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA.;Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark..
    Prescott, Moire K. M.
    New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA.;Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark..
    Oppenheimer, B. D.
    Univ Colorado, Dept Astrophys & Planetary Sci, CASA, 389 UCB, Boulder, CO 80309 USA..
    Dave, Romeel
    Univ Western Cape, Dept Phys, ZA-7535 Cape Town, South Africa.;South African Astron Observ, ZA-7525 Cape Town, South Africa.;African Inst Math Sci, ZA-7545 Cape Town, South Africa..
    Zackrisson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Livermore, R. C.
    Univ Texas Austin, 2515 Speedway,Stop C1400, Austin, TX 78712 USA..
    Finkelstein, S. L.
    Univ Texas Austin, 2515 Speedway,Stop C1400, Austin, TX 78712 USA..
    Thompson, Robert
    Univ Illinois, NCSA, Urbana, IL 61820 USA..
    Huang, Shuiyao
    Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA..
    The minimum halo mass for star formation at z=6-82017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 464, no 2, p. 1633-1639Article in journal (Refereed)
    Abstract [en]

    Recent analysis of strongly lensed sources in the Hubble Frontier Fields indicates that the rest-frame UV luminosity function of galaxies at z=6-8 rises as a power law down to M-UV=-15, and possibly as faint as-12.5. We use predictions from a cosmological radiation hydrodynamic simulation to map these luminosities on to physical space, constraining the minimum dark matter halo mass and stellar mass that the Frontier Fields probe. While previously published theoretical studies have suggested or assumed that early star formation was suppressed in haloes less massive than 10(9)-10(11) M-circle dot, we find that recent observations demand vigorous star formation in haloes at least as massive as (3.1, 5.6, 10.5) x10(9) M-circle dot at z =(6, 7, 8). Likewise, we find that Frontier Fields observations probe down to stellar masses of (8.1, 18, 32) x10(6) M-circle dot: that is, they are observing the likely progenitors of analogues to Local Group dwarfs such as Pegasus and M32. Our simulations yield somewhat different constraints than two complementary models that have been invoked in similar analyses, emphasizing the need for further observational constraints on the galaxy-halo connection.

  • 31. Folsom, C. P.
    et al.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Wade, G. A.
    Silvester, J.
    Bagnulo, S.
    Magnetic field, chemical composition and line profile variability of the peculiar eclipsing binary star AR Aur2010In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 407, no 4, p. 2383-2392Article in journal (Refereed)
    Abstract [en]

    AR Aur is the only eclipsing binary known to contain a HgMn star, making it an ideal case for a detailed study of the HgMn phenomenon. HgMn stars are a poorly understood class of chemically peculiar stars, which have traditionally been thought not to possess significant magnetic fields. However, the recent discovery of line profile variability in some HgMn stars, apparently attributable to surface abundance patches, has brought this belief into question. In this paper we investigate the chemical abundances, line profile variability, and magnetic field of the primary and secondary of the AR Aur system, using a series of high-resolution spectropolarimetric observations. We find the primary is indeed a HgMn star, and present the most precise abundances yet determined for this star. We find the secondary is a weak Am star, and is possibly still on the pre-main sequence. Line profile variability was observed in a range of lines in the primary, and is attributed to inhomogeneous surface distributions of some elements. No magnetic field was detected in any observation of either stars, with an upper limit on the longitudinal magnetic field in both stars of 100 G. Modelling of the phase-resolve longitudinal field measurements leads to a 3 Sigma upper limit on any dipole surface magnetic field of about 400 G.

  • 32. Folsom, C. P.
    et al.
    Likuski, K.
    Wade, G. A.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Alecian, E.
    Shulyak, D.
    Orbital parameters, chemical composition and magnetic field of the Ap binary HD 980882013In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 431, no 2, p. 1513-1527Article in journal (Refereed)
    Abstract [en]

    HD 98088 is a synchronized, double-lined spectroscopic binary system with a magnetic Ap primary component and an Am secondary component. We study this rare system using high-resolution Multi-Site Continuous Spectroscopy spectropolarimetric data, to gain insight into the effect of binarity on the origin of stellar magnetism and the formation of chemical peculiarities in A-type stars. Using a new collection of 29 high-resolution Stokes VQU spectra we re-derive the orbital and stellar physical parameters and conduct the first disentangling of spectroscopic observations of the system to conduct spectral analysis of the individual stellar components. From this analysis we determine the projected rotational velocities of the stars and conduct a detailed chemical abundance analysis of each component using both the SYNTH3 and ZEEMAN spectrum synthesis codes. The surface abundances of the primary component are typical of a cool Ap star, while those of the secondary component are typical of an Am star. We present the first magnetic analysis of both components using modern data. Using least-squares deconvolution, we extract the longitudinal magnetic field strength of the primary component, which is observed to vary between +1170 and -920 G with a period consistent with the orbital period. There is no field detected in the secondary component. The magnetic field in the primary is predominantly dipolar, with the positive pole oriented approximately towards the secondary.

  • 33. Folsom, C. P.
    et al.
    Wade, G. A.
    Kochukhov, O.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Alecian, E.
    Catala, C.
    Bagnulo, S.
    Boehm, T.
    Bouret, J.-C.
    Donati, J.-F.
    Grunhut, J.
    Hanes, D. A.
    Landstreet, J. D.
    Magnetic fields and chemical peculiarities of the very young intermediate-mass binary system HD 721062008In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 391, no 2, p. 901-914Article in journal (Refereed)
    Abstract [en]

    The recently discovered magnetic Herbig Ae and Be stars may provide qualitatively new information about the formation and evolution of magnetic Ap and Bp stars. We have performed a detailed investigation of one particularly interesting binary system with a Herbig Ae secondary and a late B-type primary possessing a strong, globally ordered magnetic field. 20 high-resolution Stokes V spectra of the system were obtained with the ESPaDOnS instrument mounted on the Canada-France-Hawaii Telescope. In these observations we see clear evidence for a magnetic field in the primary, but no evidence for a magnetic field in the secondary. A detailed abundance analysis was performed for both stars, revealing strong chemical peculiarities in the primary and normal chemical abundances in the secondary. The primary is strongly overabundant in Si, Cr and other iron-peak elements, as well as Nd, and underabundant in He. The primary therefore appears to be a very young Bp star. In this context, line profile variations of the primary suggest non-uniform lateral distributions of surface abundances. Interpreting the 0.639 95 +/- 0.000 09 d variation period of the Stokes I and V profiles as the rotational period of the star, we have modelled the magnetic field geometry and the surface abundance distributions of Si, Ti, Cr and Fe using magnetic Doppler imaging. We derive a dipolar geometry of the surface magnetic field, with a polar strength B-d = 1230 G and an obliquity beta = 57 degrees. The distributions Ti, Cr and Fe are all qualitatively similar, with an elongated patch of enhanced abundance situated near the positive magnetic pole. The Si distribution is somewhat different, and its relationship to the magnetic field geometry less clear.

  • 34. Fossati, L.
    et al.
    Folsom, C. P.
    Bagnulo, S.
    Grunhut, J. H.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Landstreet, J. D.
    Paladini, C.
    Wade, G. A.
    A detailed spectroscopic analysis of the open cluster NGC 54602011In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 413, no 2, p. 1132-1144Article in journal (Refereed)
    Abstract [en]

    Within the context of a large project aimed at studying early F-, A- and late B-type stars, we present the abundance analysis of the photospheres of 21 members of the open cluster NGC 5460, an intermediate-age cluster (log t similar to 8.2) previously not studied with spectroscopy. Our study is based on medium- and high-resolution spectra obtained with the Fibre Large Array Multi Element Spectrograph (FLAMES) instrument of the European Southern Observatory/Very Large Telescope. We show that cluster members have a nearly solar metallicity and that there is evidence that the abundances of magnesium and iron are correlated with the effective temperature, exhibiting a maximum around T-eff = 10 500 K. No correlations are found between abundances and projected equatorial velocity, except for marginal evidence of barium being more abundant in slower than in faster rotating stars. We discovered two He-weak stars and a binary system where the hotter component is an HgMn star. We provide new estimates for the cluster distance (720 +/- 50 pc), age (log t = 8.2 +/- 0.1) and mean radial velocity (-17.9 +/- 5.2 km s-1).

  • 35. Fossati, L.
    et al.
    Kolenberg, K.
    Shulyak, D. V.
    Elmasli, A.
    Tsymbal, V.
    Barnes, T. G.
    Guggenberger, E.
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    An in-depth spectroscopic analysis of RR Lyr Variations over the pulsation cycle2014In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 445, no 4, p. 4094-4104Article in journal (Refereed)
    Abstract [en]

    The stellar parameters of RR Lyrae stars vary considerably over a pulsation cycle, and their determination is crucial for stellar modelling. We present a detailed spectroscopic analysis of the pulsating star RR Lyr, the prototype of its class, over a complete pulsation cycle, based on high-resolution spectra collected at the 2.7-m telescope of McDonald Observatory. We used simultaneous photometry to determine the accurate pulsation phase of each spectrum and determined the effective temperature, the shape of the depth-dependent microturbulent velocity, and the abundance of several elements, for each phase. The surface gravity was fixed to 2.4. Element abundances resulting from our analysis are stable over the pulsation cycle. However, a variation in ionization equilibrium is observed around minimum radius. We attribute this mostly to a dynamical acceleration contributing to the surface gravity. Variable turbulent convection on time-scales longer than the pulsation cycle has been proposed as a cause for the Blazhko effect. We test this hypothesis to some extent by using the derived variable depth-dependent microturbulent velocity profiles to estimate their effect on the stellar magnitude. These effects turn out to be wavelength dependent and much smaller than the observed light variations over the Blazhko cycle: if variations in the turbulent motions are entirely responsible for the Blazhko effect, they must surpass the scales covered by the microturbulent velocity. This work demonstrates the possibility of a self-consistent spectroscopic analysis over an entire pulsation cycle using static atmosphere models, provided one takes into account certain features of a rapidly pulsating atmosphere.

  • 36.
    Fulle, Marco
    et al.
    INAF, Osservatorio Astron, Via Tiepolo 11, I-34143 Trieste, Italy.
    Bertini, I.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Ossevatorio 3, I-35122 Padua, Italy.
    Della Corte, V.
    INAF, Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy;Univ Napoli Parthenope, Dip Sci & Technol, CDN IC4, I-80143 Naples, Italy.
    Guttler, C.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    Ivanovski, S.
    INAF, Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy;Univ Napoli Parthenope, Dip Sci & Technol, CDN IC4, I-80143 Naples, Italy.
    La Forgia, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Ossevatorio 3, I-35122 Padua, Italy.
    Lasue, J.
    Uni Tolouse, UPS OMP, IRAP, I-31400 Toulouse, France;CNRS, IRAP, 9 Ave Colonel Roche,BP 44346, E-31028 Toulouse 4, France.
    Levasseur-Regourd, A. C.
    Sorbonne Univ, UVSQ UPSay, CNRS INSU, LATMOS IPSL, BC 102,Campus UPMC,4 Pl Jussieu, F-75005 Paris, France.
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Ossevatorio 3, I-35122 Padua, Italy.
    Moreno, F.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain.
    Mottola, S.
    Inst Planetenforsch, Deutsch Zentrum Luft & Raumfahrt DLR, Rutherfordstr 2, D-12489 Berlin, Germany.
    Naletto, G.
    Univ Padua, Dept Phys & Astron G Galilei, Via Marzolo 8, I-35131 Padua, Italy;Univ Padua, Ctr Studies & Act Space, CISAS, Via Venezia 15, I-35131 Padua, Italy;CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.
    Palumbo, P.
    Univ Napoli Parthenope, Dip Sci & Technol, CDN IC4, I-80143 Naples, Italy.
    Rinaldi, G.
    INAF, Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy;Univ Napoli Parthenope, Dip Sci & Technol, CDN IC4, I-80143 Naples, Italy.
    Rotundi, A.
    Univ Napoli Parthenope, Dip Sci & Technol, CDN IC4, I-80143 Naples, Italy.
    Sierks, H.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Ossevatorio 3, I-35122 Padua, Italy.
    Lamy, P. L.
    CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille 13, France;Aix Marseille Univ, F-13388 Marseille 13, France.
    Rodrigo, R.
    CSIC, Ctr Astrobiol, INTA, E-28850 Madrid, Spain;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland.
    Koschny, D.
    ESA, Sci Support Off, European Space Res & Technol Ctr, Keplerlaan 1,Postbus 299, NL-2201 AZ Noordwijk, Netherlands.
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Space Res Ctr, Bartycka 18A, PL-00716 Warsaw, Poland.
    Barucci, M. A.
    Univ Paris 06, UPMC, Sorbonne Univ,Observ Paris, Sorbonne Paris Cite,Univ Paris Diderot,PSL Res Un, 5 Pl Jules Janssen, F-11111 Paris, France.
    Bertaux, J. -L
    Bodewits, D.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA.
    Cremonese, G.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.
    Davidsson, B.
    Jet Prop Lab, M-S 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA.
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy.
    De Cecco, M.
    Univ Trento, Fac Engn, Via Mesiano 77, I-38121 Trento, Italy.
    Deller, J.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    Fornasier, S.
    Univ Paris 06, UPMC, Sorbonne Univ,Observ Paris, Sorbonne Paris Cite,Univ Paris Diderot,PSL Res Un, 5 Pl Jules Janssen, F-11111 Paris, France.
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France.
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain.
    Hviid, H. S.
    Inst Planetenforsch, Deutsch Zentrum Luft & Raumfahrt DLR, Rutherfordstr 2, D-12489 Berlin, Germany.
    Ip, W. H.
    Natl Cent Univ, Grad Inst Astron, 300 Chung Da Rd, Chungli 32054, Taiwan;Macau Univ Sci & Technol, Space Sci Inst, Ave Wal Long, Taipa, Macao, Peoples R China.
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France.
    Keller, H. U.
    Inst Planetenforsch, Deutsch Zentrum Luft & Raumfahrt DLR, Rutherfordstr 2, D-12489 Berlin, Germany;Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany.
    Knollenberg, J.
    Inst Planetenforsch, Deutsch Zentrum Luft & Raumfahrt DLR, Rutherfordstr 2, D-12489 Berlin, Germany.
    Kramm, J. R.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    Kuhrt, E.
    Inst Planetenforsch, Deutsch Zentrum Luft & Raumfahrt DLR, Rutherfordstr 2, D-12489 Berlin, Germany.
    Kuppers, M.
    ESA, European Space Astron Ctr, Operat Dept, POB 78, E-28691 Madrid, Spain.
    Lara, M. L.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain.
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Ossevatorio 3, I-35122 Padua, Italy.
    Lopez-Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain.
    Shi, X.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland;Univ Bern, Ctr Space & Habitabil, CH-3012 Bern, Switzerland.
    Tubiana, C.
    Max Planck Inst Stromungsforsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany.
    The phase function and density of the dust observed at comet 67P/Churyumov-Gerasimenko2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 476, no 2, p. 2835-2839Article in journal (Refereed)
    Abstract [en]

    The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observed close to Rosetta by OSIRIS, occurring about every hour, consistent with the fragmentation on impact with Rosetta of parent particles, whose flux agrees with the dust flux observed by GIADA. OSIRIS also measured the antisunward acceleration of the fragments, thus providing the first direct measurement of the solar radiation force acting on the dust fragments and thus of their bulk density, excluding any measurable rocket effect by the ice sublimation from the dust. The obtained particle density distribution has a peak matching the bulk density of most COSIMA particles, and represents a subset of the density distribution measured by GIADA. This implies a bias in the elemental abundances measured by COSIMA, which thus are consistent with the 67P dust mass fractions inferred by GIADA, i.e. (38 +/- 8) per cent of hydrocarbons versus the (62 +/- 8) per cent of sulphides and silicates.

  • 37.
    Fuselier, S. A.
    et al.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Altwegg, K.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Balsiger, H.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Berthelier, J. J.
    LATMOS, 4 Ave Neptune, F-94100 St Maur, France..
    Beth, A.
    Imperial Coll London, Dept Phys, Space & Atmospher Phys Grp, Prince Consort Rd, London SW7 2AZ, England..
    Bieler, A.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland.;Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    Briois, C.
    Univ Orleans, CNRS, Lab Phys & Chim Environm & Espace LPC2E, UMR 6115, F-45071 Orleans, France..
    Broiles, T. W.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA..
    Burch, J. L.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA..
    Calmonte, U.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Cessateur, G.
    Belgian Inst Space Aeron BIRA IASB, Ringlaan 3, B-1180 Brussels, Belgium..
    Combi, M.
    Imperial Coll London, Dept Phys, Space & Atmospher Phys Grp, Prince Consort Rd, London SW7 2AZ, England..
    De Keyser, J.
    Belgian Inst Space Aeron BIRA IASB, Ringlaan 3, B-1180 Brussels, Belgium..
    Fiethe, B.
    TU Braunschweig, Inst Comp & Network Engn IDA, Hans Sommer Str 66, D-38106 Braunschweig, Germany..
    Galand, M.
    Imperial Coll London, Dept Phys, Space & Atmospher Phys Grp, Prince Consort Rd, London SW7 2AZ, England..
    Gasc, S.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Gombosi, T. I.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    Gunell, H.
    Belgian Inst Space Aeron BIRA IASB, Ringlaan 3, B-1180 Brussels, Belgium..
    Hansen, K. C.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward, Ann Arbor, MI 48109 USA..
    Hassig, M.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA..
    Heritier, K. L.
    Imperial Coll London, Dept Phys, Space & Atmospher Phys Grp, Prince Consort Rd, London SW7 2AZ, England..
    Korth, A.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Le Roy, L.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Luspay-Kuti, A.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA..
    Mall, U.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Mandt, K. E.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Petrinec, S. M.
    Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA..
    Reme, H.
    Univ Toulouse, UPS OMP, IRAP, F-31400 Toulouse, France.;CNRS, IRAP, 9 Ave Colonel Roche,BP 44346, F-31028 Toulouse 4, France..
    Rinaldi, M.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA..
    Rubin, M.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Semon, T.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Trattner, K. J.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA..
    Tzou, C. -Y
    Vigren, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Waite, J. H.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA.;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX 78249 USA..
    Wurz, P.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Ion chemistry in the coma of comet 67P near perihelion2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S67-S77Article in journal (Refereed)
    Abstract [en]

    The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

  • 38.
    Gaidos, E.
    et al.
    Univ Hawaii Manoa, Dept Geol & Geophys, Honolulu, HI 96822 USA..
    Mann, A. W.
    Univ Texas Austin, Dept Astron, Austin, TX 78712 USA..
    Rizzuto, A.
    Univ Texas Austin, Dept Astron, Austin, TX 78712 USA..
    Nofi, L.
    Univ Hawaii Manoa, Inst Astron, Honolulu, HI 96822 USA..
    Mace, G.
    Univ Texas Austin, Dept Astron, Austin, TX 78712 USA..
    Vanderburg, A.
    Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA..
    Feiden, Gregory
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Narita, N.
    Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130038, Japan.;Natl Inst Nat Sci, Astrobiol Ctr, Mitaka, Tokyo 1818588, Japan.;Natl Astron Observ Japan, Mitaka, Tokyo 1818588, Japan.;SOKENDAI Grad Univ Adv Studies, Mitaka, Tokyo 1818588, Japan..
    Takeda, Y.
    Natl Astron Observ Japan, Mitaka, Tokyo 1818588, Japan..
    Esposito, T. M.
    Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA..
    De Rosa, R. J.
    Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA..
    Ansdell, M.
    Univ Hawaii Manoa, Inst Astron, Honolulu, HI 96822 USA..
    Hirano, T.
    Tokyo Inst Technol, Dept Earth & Planetary Sci, Meguro Ku, Tokyo 1528551, Japan..
    Graham, J. R.
    Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA..
    Kraus, A.
    Univ Texas Austin, Dept Astron, Austin, TX 78712 USA..
    Jaffe, D.
    Univ Texas Austin, Dept Astron, Austin, TX 78712 USA..
    Zodiacal exoplanets in time (ZEIT) - II. A 'super-Earth' orbiting a young K dwarf in the Pleiades Neighbourhood2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 464, no 1, p. 850-862Article in journal (Refereed)
    Abstract [en]

    We describe a 'super-Earth'-size (2.30 +/- 0.16 R-circle plus)planet transiting an early K-type dwarf star in the Campaign 4 field observed by the K2 mission. The host star, EPIC 210363145, was identified as a candidate member of the approximately 120 Myr-old Pleiades cluster based on its kinematics and photometric distance. It is rotationally variable and exhibits near-ultraviolet emission consistent with a Pleiades age, but its rotational period is approximate to 20 d and its spectrum contains no H alpha emission nor the Li I absorption expected of Pleiades K dwarfs. Instead, the star is probably an interloper that is unaffiliated with the cluster, but younger (less than or similar to 1.3 Gyr) than the typical field dwarf. We ruled out a false positive transit signal produced by confusion with a background eclipsing binary by adaptive optics imaging and a statistical calculation. Doppler radial velocity measurements limit the companion mass to <2 times that of Jupiter. Screening of the light curves of 1014 potential Pleiades candidate stars uncovered no additional planets. An injection-and-recovery experiment using the K2 Pleiades light curves with simulated planets, assuming a planet population like that in the Kepler prime field, predicts only 0.8-1.8 detections (versus similar to 20 in an equivalent Kepler sample). The absence of Pleiades planet detections can be attributed to the much shorter monitoring time of K2 (80 d versus 4 yr), increased measurement noise due to spacecraft motion, and the intrinsic noisiness of the stars.

  • 39.
    Galand, M.
    et al.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Heritier, K. L.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Odelstad, Elias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Henri, P.
    Univ Orleans, CNRS, LPC2E, 3A,Ave Rech Sci, F-45071 Orleans 2, France..
    Broiles, T. W.
    Southwest Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA..
    Allen, A. J.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Altwegg, K.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Beth, A.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Burch, J. L.
    Southwest Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA..
    Carr, C. M.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Cupido, E.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Glassmeier, K. -H
    Johansson, Fredrik L.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lebreton, J. -P
    Mandt, K. E.
    Southwest Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA..
    Nilsson, H.
    Swedish Inst Space Phys, POB 812, SE-98128 Kiruna, Sweden..
    Richter, I.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Rubin, M.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Sagnieres, L. B. M.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Schwartz, S. J.
    Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England..
    Semon, T.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Tzou, C. -Y
    Vallieres, X.
    Univ Orleans, CNRS, LPC2E, 3A,Ave Rech Sci, F-45071 Orleans 2, France..
    Vigren, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Wurz, P.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Ionospheric plasma of comet 67P probed by Rosetta at 3 au from the Sun2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S331-S351Article in journal (Refereed)
    Abstract [en]

    We propose to identify the main sources of ionization of the plasma in the coma of comet 67P/Churyumov-Gerasimenko at different locations in the coma and to quantify their relative importance, for the first time, for close cometocentric distances (< 20 km) and large heliocentric distances (> 3 au). The ionospheric model proposed is used as an organizing element of a multi-instrument data set from the Rosetta Plasma Consortium (RPC) plasma and particle sensors, from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis and from the Microwave Instrument on the Rosetta Orbiter, all on board the ESA/Rosetta spacecraft. The calculated ionospheric density driven by Rosetta observations is compared to the RPC-Langmuir Probe and RPC-Mutual Impedance Probe electron density. The main cometary plasma sources identified are photoionization of solar extreme ultraviolet (EUV) radiation and energetic electron-impact ionization. Over the northern, summer hemisphere, the solar EUV radiation is found to drive the electron density - with occasional periods when energetic electrons are also significant. Over the southern, winter hemisphere, photoionization alone cannot explain the observed electron density, which reaches sometimes higher values than over the summer hemisphere; electron-impact ionization has to be taken into account. The bulk of the electron population is warm with temperature of the order of 7-10 eV. For increased neutral densities, we show evidence of partial energy degradation of the hot electron energy tail and cooling of the full electron population.

  • 40.
    Georgakarakos, Nikolaos
    et al.
    New York Univ Abu Dhabi, POB 129188, Abu Dhabi, U Arab Emirates..
    Dobbs-Dixon, Ian
    New York Univ Abu Dhabi, POB 129188, Abu Dhabi, U Arab Emirates..
    Way, Michael J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. NASA, Goddard Inst Space Studies, New York, NY 10027 USA..
    Long-term evolution of planetary systems with a terrestrial planet and a giant planet2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 461, no 2, p. 1512-1528Article in journal (Refereed)
    Abstract [en]

    We study the long-term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the smaller planet. The perturbing potential is expanded to high orders, and an analytical solution of the terrestrial planetary orbit is derived. The analytical estimates are then compared against results from the numerical integration of the full equations of motion, and we find that the analytical solution works reasonably well. An interesting finding is that the new analytical estimates improve greatly the predictions for the time-scales of the orbital evolution of the terrestrial planet compared to an octupole order expansion. Finally, we briefly discuss possible applications of the analytical estimates in astrophysical problems.

  • 41.
    Giacomini, L.
    et al.
    Univ Padua, Dipartimento Geosci, Via G Gradenigo 6, I-35131 Padua, Italy..
    Massironi, M.
    Univ Padua, Dipartimento Geosci, Via G Gradenigo 6, I-35131 Padua, Italy..
    El-Maarry, M. R.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Penasa, L.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    Pajola, M.
    NASA Ames Res Ctr, Moffett Field, CA 94035 USA..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Lowry, S. C.
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NZ, Kent, England..
    Barbieri, C.
    Univ Padua, Dipartimento Fis & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Cremonese, G.
    INAF Osservatorio Astron Padova, Vic Osservatorio 5, I-35122 Padua, Italy..
    Ferri, F.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    Naletto, G.
    Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Bertini, I.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, Via Venezia 15, I-35131 Padua, Italy..
    La Forgia, F.
    Univ Padua, Dipartimento Fis & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lazzarin, M.
    Univ Padua, Dipartimento Fis & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Marzari, F.
    Univ Padua, Dipartimento Fis & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Lamy, P. L.
    CNRS, UMR 7236, Lab Astrophys Marseille, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France.;Aix Marseille Univ, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France..
    Rodrigo, R.
    CSIC INTA, Ctr Astrobiol, E-28850 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Poland.
    Koschny, D.
    European Space Res & Technol Ctr ESA, Sci Support Off, Keplerlaan 1,Postbus 299, NL-2201 AZ Noordwijk, Netherlands..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, 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, UPMC, LESIA Observ Paris,CNRS, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Besse, S.
    European Space Res & Technol Ctr ESA, Sci Support Off, Keplerlaan 1,Postbus 299, NL-2201 AZ Noordwijk, Netherlands..
    Bodewits, D.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    De Cecco, M.
    Univ Trento, Via Sommar 9, I-38123 Trento, Italy..
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, UPMC, LESIA Observ Paris,CNRS, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Fulle, M.
    INAF Osservatorio Astron Trieste, Via Tiepolo 11, I-34014 Trieste, Italy..
    Groussin, O.
    CNRS, UMR 7236, Lab Astrophys Marseille, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France.;Aix Marseille Univ, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France..
    Gutierrez, P. J.
    Inst Astrofis Andalucia CSIC, E-18008 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    Inst Planeten Forsch, Deutsch Zentrum Luft & Raumfahrt, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W. -H
    Jorda, L.
    CNRS, UMR 7236, Lab Astrophys Marseille, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France.;Aix Marseille Univ, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France..
    Knollenberg, J.
    Inst Planeten Forsch, Deutsch Zentrum Luft & Raumfahrt, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kovacs, G.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Kramm, J. -R
    Kuehrt, E.
    Inst Planeten Forsch, Deutsch Zentrum Luft & Raumfahrt, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    European Space Astron Ctr ESA, Operat Dept, POB 78, E-28691 Madrid, Spain..
    Lara, L. M.
    Inst Astrofis Andalucia CSIC, E-18008 Granada, Spain..
    Lopez Moreno, J. J.
    Inst Astrofis Andalucia CSIC, E-18008 Granada, Spain..
    Magrin, S.
    Univ Padua, Dipartimento Fis & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Michalik, H.
    TU Braunschweig, Inst Datentech & Kommunikat Netze, Hans Sommer Str 66, D-38106 Braunschweig, Germany..
    Oklay, N.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Pommerol, A.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Preusker, F.
    Inst Planeten Forsch, Deutsch Zentrum Luft & Raumfahrt, Rutherfordstr 2, D-12489 Berlin, Germany..
    Scholten, F.
    Inst Planeten Forsch, Deutsch Zentrum Luft & Raumfahrt, Rutherfordstr 2, D-12489 Berlin, Germany..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Geologic mapping of the Comet 67P/Churyumov-Gerasimenko's Northern hemisphere2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S352-S369Article in journal (Refereed)
    Abstract [en]

    The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS), the scientific imaging system onboard the Rosetta mission, has been acquiring images of the nucleus of the comet 67P/Churyumov-Gerasimenko since 2014 August with a resolution which allows a detailed analysis of its surface. Indeed, data reveal a complex surface morphology which is likely the expression of different processes which occurred at different times on the cometary nucleus. In order to characterize these different morphologies and better understand their distribution, we performed a geologic mapping of comet's 67P Northern hemisphere in which features have been distinguished based on their morphological, textural and stratigraphic characteristics. For this purpose, we used narrow-angle camera images acquired in 2014 August and September with a spatial scale ranging from 1.2 to 2.4 m pixel(-1). Several different geologic units have been identified on the basis of their different surface textures, granulometry and morphology. Some of these units are distinctive and localized, whereas others are more common and distributed all over the Northern hemisphere. Moreover, different types of linear features have been distinguished on the basis of their morphology. Some of these lineaments have never been observed before on a comet and can offer important clues on the internal structures of the nucleus itself. The geologic mapping results presented here will allow us to better understand the processes which affected the nucleus' surface and thus the origin and evolutionary history of comet 67P/Churyumov-Gerasimenko.

  • 42.
    Gicquel, A.
    et al.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Bertini, I.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy..
    Bodewits, D.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Li, Z. -Y
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P. L.
    Aix Marseille Univ, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille, France..
    Rodrigo, R.
    ESAC, European Space Agcy, CSIC, Ctr Astrobiol,INTA, POB 78, E-28691 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 AZ Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Poland.
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Barucci, M. A.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon Pricipal, France..
    Bertaux, J. -L
    Besse, S.
    European Space Agcy, Res & Sci Support Dept, NL-2201 AZ Noordwijk, Netherlands..
    Cremonese, G.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, 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, Via Venezia 1, I-35131 Padua, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    De Cecco, M.
    Univ Trento, Via Sommarive 9, I-38123 Trento, Italy..
    Frattin, E.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    El-Maarry, M. R.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Fornasier, S.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon Pricipal, France..
    Fulle, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34143 Trieste, Italy..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Gutierrez-Marquez, P.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hoefner, S.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany.;TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Hofmann, M.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hu, X.
    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. -H
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kovacs, G.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany.;Budapest Univ Technol & Econ, Dept Mechatron Opt & Engn Informat, Muegyet Rkp 3, H-1111 Budapest, Hungary..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kueppers, M.
    ESAC, ESA, POB 78, E-28691 Villanueva De La Canada, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Lowry, S.
    Univ Kent, Sch Phys Sci, Ctr Astrophys & Planetary Sci, Canterbury CT2 7NH, Kent, England..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Masoumzadeh, N.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Massironi, M.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy..
    Moreno, F.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Mottola, S.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Naletto, G.
    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.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Pajola, M.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy..
    Pommerol, A.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Preusker, F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Scholten, F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Shi, X.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Toth, I.
    Aix Marseille Univ, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille, France.;Observ Hungarian Acad Sci, POB 67, H-1525 Budapest, Hungary..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Sublimation of icy aggregates in the coma of comet 67P/Churyumov-Gerasimenko detected with the OSIRIS cameras on board Rosetta2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S57-S66Article in journal (Refereed)
    Abstract [en]

    Beginning in 2014 March, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov-Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet's dust jets. We analysed the dust monitoring observations shortly after the southern vernal equinox on 2015 May 30 and 31 with the WAC at the heliocentric distance R-h = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness as a function of the distance of the jet is much steeper than the background coma, which is a first indication of sublimation. We adapted a model of sublimation of icy aggregates and studied the effect as a function of the physical properties of the aggregates (composition and size). The major finding of this paper was that through the sublimation of the aggregates of dirty grains (radius a between 5 and 50 mu m) we were able to completely reproduce the radial brightness profile of a jet beyond 4 km from the nucleus. To reproduce the data, we needed to inject a number of aggregates between 8.5 x 10(13) and 8.5 x 10(10) for a = 5 and 50 mu m, respectively, or an initial mass of H2O ice around 22 kg.

  • 43.
    Goetz, C.
    et al.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Koenders, C.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Hansen, K. C.
    Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward St, Ann Arbor, MI 48109 USA..
    Burch, J.
    Southwest Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA..
    Carr, C.
    Imperial Coll London, Space & Atmospher Phys Grp, Exhibit Rd, London SW7 2AZ, England..
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Fruehauff, D.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Guettler, C.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Henri, P.
    Univ Orleans, CNRS, UMR 7328, Lab Phys & Chim Environm & Espace, F-45100 Orleans, France..
    Nilsson, H.
    Swedish Inst Space Phys, POB 812, SE-98128 Kiruna, Sweden..
    Richter, I.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Rubin, M.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Sierks, H.
    Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Tsurutani, B.
    CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Volwerk, M.
    Austrian Acad Sci, Inst Weltraumforsch, Schmiedlstr 6, A-8042 Graz, Austria..
    Glassmeier, K. H.
    TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany.;Max Planck Inst Sonnensyst Forschung, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Structure and evolution of the diamagnetic cavity at comet 67P/Churyumov-Gerasimenko2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S459-S467Article in journal (Refereed)
    Abstract [en]

    The long duration of the Rosetta mission allows us to study the evolution of the diamagnetic cavity at comet 67P/Churyumov-Gerasimenko in detail. From 2015 April to 2016 February 665 intervals could be identified where Rosetta was located in a zero-magnetic-field region. We study the temporal and spatial distribution of this cavity and its boundary and conclude that the cavity properties depend on the long-term trend of the outgassing rate, but do not respond to transient events at the spacecraft location, such as outbursts or high neutral densities. Using an empirical model of the outgassing rate, we find a functional relationship between the outgassing rate and the distance of the cavity to the nucleus. There is also no indication that this unexpectedly large distance is related to unusual solar wind conditions. Because the deduced shape of the cavity boundary is roughly elliptical on small scales and the distances of the boundary from the nucleus are much larger than expected we conclude that the events observed by Rosetta are due to a moving instability of the cavity boundary itself.

  • 44. Goswami, Aruna
    et al.
    Aoki, Wako
    Beers, Timothy C.
    Christlieb, Norbert
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Norris, John E.
    Ryan, Sean G.
    Tsangarides, Stelios
    A high-resolution spectral analysis of three carbon-enhanced metal-poor stars2006In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 372, no 1, p. 343-356Article in journal (Refereed)
    Abstract [en]

    We present results of an analysis of high-resolution spectra (R similar to 50 000), obtained with the Subaru Telescope High Dispersion Spectrograph, of two carbon-enhanced metal-poor (CEMP) stars selected from the Hamburg/European Southern Observatory prism survey, HE 1305+0007 and HE 1152-0355, and of the classical CH star HD 5223. All these stars have relatively low effective temperatures (4000-4750 K) and high carbon abundances, which result in the presence of very strong molecular carbon bands in their spectra. The stellar atmospheric parameters for these stars indicate that they all have surface gravities consistent with a present location on the red giant branch, and metallicities of [Fe/H] = -2.0 (HE 1305+0007, HD 5223) and [Fe/H] = -1.3 (HE 1152-0355). In addition to their large enhancements of carbon ([C/Fe] = +1.8, +1.6, and +0.6, respectively), all three stars exhibit strong enhancements of the s-process elements relative to iron. HE 1305+0007 exhibits a large enhancement of the third-peak s-process element, lead, with [Pb/Fe] = +2.37, as well as a high abundance of the r-process element europium, [Eu/Fe] = +1.97. The second-peak s-process elements, Ba, La, Ce, Nd and Sm, are found to be more enhanced than the first-peak s-process elements Zr, Sr and Y. Thus, HE 1305+0007 joins the growing class of the so-called 'Lead stars', and also the class of objects that exhibit the presence of both r- and s-process elements, the CEMP-r/s stars. The large enhancements of neutron-capture (n-capture) elements exhibited by HE 1152-0355 and HD 5223 are more consistent with the abundance patterns generally noticed in CH stars, essentially arising from pure s-process nucleosynthesis. The elemental abundance distributions observed in these stars are discussed in light of existing theories of CH star formation, as well as the suggested formation scenarios of the CEMP-r/s group.

  • 45.
    Grun, E.
    et al.
    Max Planck Inst Kernphys, Saupfercheckweg 1, D-69127 Heidelberg, Germany.;Univ Colorado, Lab Atmospher & Space Phys, 1234 Innovat Dr, Boulder, CO 80303 USA..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Altobelli, N.
    ESA, Camino Bajo Castillo S-N, E-28692 Madrid, Spain..
    Altwegg, K.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Bentley, M. S.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria..
    Biver, N.
    Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Della Corte, V.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy..
    Edberg, Niklas J. T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Feldman, P. D.
    Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA..
    Galand, M.
    Imperial Coll, South Kensington Campus, London SW7 2AZ, England..
    Geiger, B.
    ESA, Camino Bajo Castillo S-N, E-28692 Madrid, Spain..
    Goetz, C.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Grieger, B.
    ESA, Camino Bajo Castillo S-N, E-28692 Madrid, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Henri, P.
    CNRS, LPC2E, Orleans, France..
    Hofstadter, M.
    CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Horanyi, M.
    Univ Colorado, Lab Atmospher & Space Phys, 1234 Innovat Dr, Boulder, CO 80303 USA..
    Jehin, E.
    Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium..
    Krueger, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Lee, S.
    CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Mannel, T.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria..
    Morales, E.
    Jaicoa Observ, Aguadilla, PR USA..
    Mousis, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Mueller, M.
    ESOC, ESA, Robert Bosch Str 5, Darmstadt, Germany..
    Opitom, C.
    Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium..
    Rotundi, A.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy.;Univ Napoli Parthenope, Dip Sci & Tecnol, CDN IC4, I-80143 Naples, Italy..
    Schmied, R.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.;Graz Univ, Inst Phys, Univ Pl 3, A-8010 Graz, Austria..
    Schmidt, F.
    Univ Stuttgart, Inst Raumfahrtsyst IRS, Pfaffenwaldring 29, D-70569 Stuttgart, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Snodgrass, C.
    Open Univ, Dept Phys Sci, Planetary & Space Sci, Milton Keynes MK7 6AA, Bucks, England..
    Soja, R. H.
    Univ Stuttgart, Inst Raumfahrtsyst IRS, Pfaffenwaldring 29, D-70569 Stuttgart, Germany..
    Sommer, M.
    Univ Stuttgart, Inst Raumfahrtsyst IRS, Pfaffenwaldring 29, D-70569 Stuttgart, Germany..
    Srama, R.
    Univ Stuttgart, Inst Raumfahrtsyst IRS, Pfaffenwaldring 29, D-70569 Stuttgart, Germany..
    Tzou, C. -Y
    Vincent, J. -B
    Yanamandra-Fisher, P.
    Space Sci Inst, 13456 Cajon Creek Court, Rancho Cucamonga, CA 91739 USA..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Barucci, M. A.
    Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giusepp Colomb, Via Venezia 15, I-35131 Padua, Italy..
    Burch, J.
    Southwest Res Inst, 6220 Culebra Rd, San Antonio, TX 78238 USA..
    Colangeli, L.
    European Space Agcy, European Space Res & Technol Ctr, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands..
    Cremonese, G.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, 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, Via Venezia 1, I-35131 Padua, Italy..
    De Cecco, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34143 Trieste, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Feaga, L. M.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Ferrari, M.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy..
    Fornasier, S.
    Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Fulle, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gicquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Gillon, M.
    Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium..
    Green, S. F.
    Open Univ, Dept Phys Sci, Planetary & Space Sci, Milton Keynes MK7 6AA, Bucks, England..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Hofmann, M.
    Hviid, S. F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W. -H
    Ivanovski, S.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy..
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Knight, M. M.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Koschny, D.
    European Space Agcy, European Space Res & Technol Ctr, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    ESA, Camino Bajo Castillo S-N, E-28692 Madrid, Spain..
    Lamy, P. L.
    CNRS, UMR 7326, Lab Astrophys Marseille, 38 Rue Federic Joliot Curie, F-13388 Marseille 13, France.;Aix Marseille Univ, 38 Rue Federic Joliot Curie, F-13388 Marseille 13, France..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Lopez-Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron S-N, E-18008 Granada, Spain..
    Manfroid, J.
    Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium..
    Epifani, E. Mazzotta
    OAR, INAF, Via Frascati 33, I-00078 Rome, Italy..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Naletto, G.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giusepp Colomb, Via Venezia 15, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Oklay, N.
    Palumbo, P.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy.;Univ Napoli Parthenope, Dip Sci & Tecnol, CDN IC4, I-80143 Naples, Italy..
    Parker, J. Wm.
    Southwest Res Inst, 1050 Walnut St,Suite 300, Boulder, CO 80302 USA..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Poland.
    Rodrigo, R.
    ESA, Camino Bajo Castillo S-N, E-28692 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Rodriguez, J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron S-N, E-18008 Granada, Spain..
    Schindhelm, E.
    Southwest Res Inst, 1050 Walnut St,Suite 300, Boulder, CO 80302 USA..
    Shi, X.
    Sordini, R.
    INAF, IAPS, Via Fosso Cavaliere, I-00133 Rome, Italy..
    Steffl, A. J.
    Southwest Res Inst, 1050 Walnut St,Suite 300, Boulder, CO 80302 USA..
    Stern, S. A.
    Southwest Res Inst, 1050 Walnut St,Suite 300, Boulder, CO 80302 USA..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Weaver, H. A.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Weissman, P.
    Planetary Sci Inst, 1700 East Ft Lowell,Suite 106, Tucson, AZ 85719 USA..
    Zakharov, V. V.
    Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France.;UPMC Univ Paris 06, CNRS, Sorbonne Univ, Lab Meteorol Dynam, 4 Pl Jussieu, F-75252 Paris, France..
    The 2016 Feb 19 outburst of comet 67P/CG: an ESA Rosetta multi-instrument study2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S220-S234Article in journal (Refereed)
    Abstract [en]

    On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

  • 46. Grunhut, H
    et al.
    Wade, A
    Marcolino, F
    Petit, V
    Henrichs, F
    Cohen, H
    Alecian, E
    Bohlender, D
    Bouret, J.-C.
    Kochukhov, O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Neiner, C
    St-Louis, N
    Townsend, D
    Discovery of a magnetic field in the O9 sub-giant star HD 57682 by the MiMeS Collaboration2009In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 400, no 1, p. L94-L98Article in journal (Refereed)
    Abstract [en]

    We report the detection of a strong, organized magnetic field in the O9IV star HD 57682, using spectropolarimetric observations obtained with ESPaDOnS at the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Programme. From the fitting of our spectra using non-local thermodynamic equilibrium model atmospheres, we determined that HD 57682 is a 17(-9)(+19)M(circle dot) star with a radius of 7.0(-1.8)(+2.4)R(circle dot) and a relatively low mass-loss rate of 1.4(-0.95)(+3.1) x 10(-9) M-circle dot yr(-1). The photospheric absorption lines are narrow, and we use the Fourier transform technique to infer v sin i = 15 +/- 3 km s(-1). This v sin i implies a maximum rotational period of 31.5 d, a value qualitatively consistent with the observed variability of the optical absorption and emission lines, as well as the Stokes V profiles and longitudinal field. Using a Bayesian analysis of the velocity-resolved Stokes V profiles to infer the magnetic field characteristics, we tentatively derive a dipole field strength of 1680(-356)(+134)G. The derived field strength and wind characteristics imply a wind that is strongly confined by the magnetic field.

  • 47.
    Grunhut, J. H.
    et al.
    European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany.;Univ Toronto, Dunlap Inst Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada..
    Wade, G. A.
    Royal Mil Coll Canada, Dept Phys, POB 17000, Kingston, ON K7K 7B4, Canada..
    Neiner, C.
    Univ Paris Diderot, UPMC Univ Paris 06, Sorbonne Univ,Sorbonne Paris Cite, LESIA,Observ Paris,PSL Res Univ,CNRS, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Oksala, M. E.
    Univ Paris Diderot, UPMC Univ Paris 06, Sorbonne Univ,Sorbonne Paris Cite, LESIA,Observ Paris,PSL Res Univ,CNRS, 5 Pl Jules Janssen, F-92195 Meudon, France.;Calif Lutheran Univ, Dept Phys, 60 West Olsen Rd 3700, Thousand Oaks, CA 91360 USA..
    Petit, V.
    Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA..
    Alecian, E.
    Univ Paris Diderot, UPMC Univ Paris 06, Sorbonne Univ,Sorbonne Paris Cite, LESIA,Observ Paris,PSL Res Univ,CNRS, 5 Pl Jules Janssen, F-92195 Meudon, France.;CNRS, INSU, UJF Grenoble 1, Inst Planetol & Astrophys Grenoble,UMR 5274, F-38041 Grenoble, France..
    Bohlender, D. A.
    Natl Res Council Canada, Herzberg Astron & Astrophys Program, Domin Astrophys Observ, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada..
    Bouret, J. -C
    Henrichs, H. F.
    Univ Amsterdam, Anton Pannekoek Inst Astron, Sci Pk 904, NL-1098 XH Amsterdam, Netherlands..
    Hussain, G. A. J.
    European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany..
    Kochukhov, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    The MiMeS survey of Magnetism in Massive Stars: magnetic analysis of the O-type stars2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 465, no 2, p. 2432-2470Article in journal (Refereed)
    Abstract [en]

    We present the analysis performed on spectropolarimetric data of 97 O-type targets included in the framework of the Magnetism in Massive Stars (MiMeS) Survey. Mean least-squares deconvolved Stokes I and V line profiles were extracted for each observation, from which we measured the radial velocity, rotational and non-rotational broadening velocities, and longitudinal magnetic field B-l. The investigation of the Stokes I profiles led to the discovery of two new multiline spectroscopic systems (HD 46106, HD 204827) and confirmed the presence of a suspected companion in HD 37041. We present a modified strategy of the leastsquares deconvolution technique aimed at optimizing the detection of magnetic signatures while minimizing the detection of spurious signatures in Stokes V. Using this analysis, we confirm the detection of a magnetic field in six targets previously reported as magnetic by the MiMeS collaboration (HD 108, HD 47129A2, HD 57682, HD 148937, CPD-28 2561, and NGC 1624-2), as well as report the presence of signal in Stokes V in three new magnetic candidates (HD 36486, HD 162978, and HD 199579). Overall, we find a magnetic incidence rate of 7 +/- 3 per cent, for 108 individual O stars (including all O-type components part of multiline systems), with a median uncertainty of the B-l measurements of about 50 G. An inspection of the data reveals no obvious biases affecting the incidence rate or the preference for detecting magnetic signatures in the magnetic stars. Similar to A- and B-type stars, we find no link between the stars' physical properties (e.g. T-eff, mass, and age) and the presence of a magnetic field. However, the Of?p stars represent a distinct class of magnetic O-type stars.

  • 48.
    Gupta, Alok C.
    et al.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China.;Aryabhatta Res Inst Observat Sci ARIES, Manora Peak 263002, Nainital, India..
    Agarwal, Aditi
    Aryabhatta Res Inst Observat Sci ARIES, Manora Peak 263002, Nainital, India..
    Mishra, Alka
    Aryabhatta Res Inst Observat Sci ARIES, Manora Peak 263002, Nainital, India..
    Gaur, H.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China..
    Wiita, P. J.
    Coll New Jersey, Dept Phys, POB 7718, Ewing, NJ 08628 USA..
    Gu, M. F.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China..
    Kurtanidze, O. M.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia.;Kazan Fed Univ, Engelhardt Astron Observ, Tatarstan 420000, Russia..
    Damljanovic, G.
    Astron Observ, Volgina 7, Belgrade 11060, Serbia..
    Uemura, M.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Semkov, E.
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Strigachev, A.
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Bachev, R.
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Vince, O.
    Astron Observ, Volgina 7, Belgrade 11060, Serbia..
    Zhang, Z.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China..
    Villarroel, Beatriz Rodriguez
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Kushwaha, P.
    Univ Sao Paulo, Dept Astron IAG USP, BR-05508900 Sao Paulo, Brazil..
    Pandey, A.
    Aryabhatta Res Inst Observat Sci ARIES, Manora Peak 263002, Nainital, India..
    Abe, T.
    Chanishvili, R.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Chigladze, R. A.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Fan, J. H.
    Guangzhou Univ, Ctr Astrophys, Guangzhou 510006, Guangdong, Peoples R China..
    Hirochi, J.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Itoh, R.
    Tokyo Inst Technol, Dept Phys, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528551, Japan..
    Kanda, Y.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Kawabata, M.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Kimeridze, G. N.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Kurtanidze, S. O.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Latev, G.
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Dimitrova, R. V. Munoz
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Nakaoka, T.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Nikolashvili, M. G.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Shiki, K.
    Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Kagamiyama 1-3-1, Higashihiroshima 7398526, Japan..
    Sigua, L. A.
    Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Rep of Georgia..
    Spassov, B.
    Bulgarian Acad Sci, Inst Astron, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria.;Bulgarian Acad Sci, Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, BU-1784 Sofia, Bulgaria..
    Multiband optical variability of the blazar OJ 287 during its outbursts in 2015-20162017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 465, no 4, p. 4423-4433Article in journal (Refereed)
    Abstract [en]

    We present recent optical photometric observations of the blazar OJ 287 taken during 2015 September-2016 May. Our intense observations of the blazar started in 2015 November and continued until 2016 May and included detection of the large optical outburst in 2015 December that was predicted using the binary black hole model for OJ 287. For our observing campaign, we used a total of nine ground-based optical telescopes of which one is in Japan, one is in India, three are in Bulgaria, one is in Serbia, one is in Georgia, and two are in the USA. These observations were carried out in 102 nights with a total of similar to 1000 image frames in BVRI bands, though the majority were in the R band. We detected a second comparably strong flare in 2016 March. In addition, we investigated multiband flux variations, colour variations, and spectral changes in the blazar on diverse time-scales as they are useful in understanding the emission mechanisms. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux, colour, and spectral variability.

  • 49.
    Hagelin, Susanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Masciadri, Elena
    Osserv Astrofis Arcetri, INAF, I-50125 Florence, Italy.
    Lascaux, F
    Osserv Astrofis Arcetri, INAF, I-50125 Florence, Italy.
    Stoesz,
    Osserv Astrofis Arcetri, INAF, I-50125 Florence, Italy.
    Comparison of the atmosphere above the South Pole, Dome C and Dome A: first attempt2008In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 387, no 4, p. 1499-1510Article in journal (Refereed)
    Abstract [en]

    The atmospheric properties above three sites (Dome C, Dome A and the South Pole) on the Internal Antarctic Plateau are investigated for astronomical applications using the monthly median of the analyses from ECMWF (the European Centre for Medium-Range Weather Forecasts). Radiosoundings extended on a yearly time-scale at the South Pole and Dome C are used to quantify the reliability of the ECMWF analyses in the free atmosphere as well as in the boundary and surface layers, and to characterize the median wind speed in the first 100 m above the two sites. Thermodynamic instability properties in the free atmosphere above the three sites are quantified with monthly median values of the Richardson number. We find that the probability to trigger thermodynamic instabilities above 100 m is smaller on the Internal Antarctic Plateau than on mid-latitude sites. In spite of the generally more stable atmospheric conditions of the Antarctic sites compared to mid-latitude sites, Dome C shows worse thermodynamic instability conditions than those predicted above the South Pole and Dome A above 100 m. A rank of the Antarctic sites done with respect to the strength of the wind speed in the free atmosphere (ECMWF analyses) as well as the wind shear in the surface layer (radiosoundings) is presented.

  • 50.
    Hagelin, Susanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Masciadri, Elena
    Lascaux, Franck
    Optical turbulence simulations at Mt Graham using the Meso-NH model2011In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 412, no 4, p. 2695-2706Article in journal (Refereed)
    Abstract [en]

    The mesoscale model Meso-NH is used to simulate the optical turbulence at Mt Graham (Arizona, USA), site of the Large Binocular Telescope. Measurements of the C2(N) profiles obtained with a generalized scidar from 41 nights are used to calibrate and quantify the model's ability to reconstruct the optical turbulence above the site. The measurements are distributed over different periods of the year, permitting us to study the model's performance in different seasons. A statistical analysis of the simulations is performed for all the most important astroclimatic parameters: the C2(N) profiles, the seeing epsilon, the isoplanatic angle theta(0) and the wavefront coherence time tau(0).

    The model shows a general good ability in reconstructing the morphology of the optical turbulence (the shape of the vertical distribution of C2(N)) as well as the strength of all the integrated astroclimatic parameters. The relative error (with respect to measurements) of the averaged seeing on the whole atmosphere for the whole sample of 41 nights is within 9.0 per cent. The median value of the relative error night by night is equal to 18.7 per cent, so that the model still maintains very good performances. Comparable percentages are observed in partial vertical slabs (free atmosphere and boundary layer) and in different seasons (summer and winter). We prove that the most urgent problem, at present, is to increase the ability of the model in reconstructing very weak and very strong turbulence conditions in the high atmosphere. This evidence in the model mainly affects, at present, the model's performances for the isoplanatic angle predictions, for which the median value of the relative error night by night is equal to 35.1 per cent. No major problems are observed for the other astroclimatic parameters. A variant to the standard calibration method is tested but we find that it does not provide better results, confirming the solid base of the standard method.

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