uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Piskunov, Nikolai
Alternative names
Publications (10 of 137) Show all publications
Regandell, S., Marquart, T. & Piskunov, N. (2018). Inside a VAMDC data node-putting standards into practical software. Physica Scripta, 93(3), Article ID 035001.
Open this publication in new window or tab >>Inside a VAMDC data node-putting standards into practical software
2018 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 93, no 3, article id 035001Article in journal (Refereed) Published
Abstract [en]

Access to molecular and atomic data is critical for many forms of remote sensing analysis across different fields. Many atomic and molecular databases are however highly specialised for their intended application, complicating querying and combination data between sources. The Virtual Atomic and Molecular Data Centre, VAMDC, is an electronic infrastructure that allows each database to register as a 'node'. Through services such as VAMDC's portal website, users can then access and query all nodes in a homogenised way. Today all major Atomic and Molecular databases are attached to VAMDC This article describes the software tools we developed to help data providers create and manage a VAMDC node. It gives an overview of the VAMDC infrastructure and of the various standards it uses. The article then discusses the development choices made and how the standards are implemented in practice. It concludes with a full example of implementing a VAMDC node using a real-life case as well as future plans for the node software.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2018
Keyword
databases, atomic and molecular physics, stellar atmospheres, data analysis, science infrastructure
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-348835 (URN)10.1088/1402-4896/aaa268 (DOI)000425690300001 ()
Available from: 2018-04-25 Created: 2018-04-25 Last updated: 2018-04-25Bibliographically approved
Piskunov, N. (2017). Main High-Resolution Near-IR Spectrometer for the VLT. In: Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA (Ed.), Stars: From Collapse To Collapse. Paper presented at Conference on Stars: From Collapse to Collapse. Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016 (pp. 514-517). , 510
Open this publication in new window or tab >>Main High-Resolution Near-IR Spectrometer for the VLT
2017 (English)In: Stars: From Collapse To Collapse / [ed] Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA, 2017, Vol. 510, p. 514-517Conference paper, Published paper (Refereed)
Abstract [en]

We present the ongoing CRISES+ project on the development of a cross dispersed high resolution near-infrared spectrometer for the ESO Very Large Telescope. The presentation highlights the relation between science objectives, technical solutions, and the structure of the project. We also share some of the insights on the implementation and management of the project that are crucial for keeping the tight time-line through efficient interaction between consortium members.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-347315 (URN)000411770200129 ()978-1-58381-904-3 (ISBN)
Conference
Conference on Stars: From Collapse to Collapse. Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016
Available from: 2018-03-29 Created: 2018-03-29 Last updated: 2018-03-29Bibliographically approved
Piskunov, N., Ryabchikova, T., Pakhomov, Y., Sitnova, T., Alekseeva, S., Mashonkina, L. & Nordlander, T. (2017). Program Package for the Analysis of High Resolution High Signal-To-Noise Stellar Spectra. In: Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA (Ed.), Stars: From Collapse To Collapse. Paper presented at Conference on Stars: From Collapse to Collapse. Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016 (pp. 509-513). , 510
Open this publication in new window or tab >>Program Package for the Analysis of High Resolution High Signal-To-Noise Stellar Spectra
Show others...
2017 (English)In: Stars: From Collapse To Collapse / [ed] Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA, 2017, Vol. 510, p. 509-513Conference paper, Published paper (Refereed)
Abstract [en]

The program package SME (Spectroscopy Made Easy), designed to perform an analysis of stellar spectra using spectral fitting techniques, was updated due to adding new functions (isotopic and hyperfine splittins) in VALD and including grids of NLTE calculations for energy levels of few chemical elements. SME allows to derive automatically stellar atmospheric parameters: effective temperature, surface gravity, chemical abundances, radial and rotational velocities, turbulent velocities, taking into account all the effects defining spectral line formation. SME package uses the best grids of stellar atmospheres that allows us to perform spectral analysis with the similar accuracy in wide range of stellar parameters and metallicities from dwarfs to giants of BAFGK spectral classes.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-347314 (URN)000411770200128 ()978-1-58381-904-3 (ISBN)
Conference
Conference on Stars: From Collapse to Collapse. Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016
Available from: 2018-03-29 Created: 2018-03-29 Last updated: 2018-03-29Bibliographically approved
Piskunov, N. & Valenti, J. A. (2017). Spectroscopy Made Easy: Evolution. Astronomy and Astrophysics, 597, Article ID A16.
Open this publication in new window or tab >>Spectroscopy Made Easy: Evolution
2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 597, article id A16Article in journal (Refereed) Published
Abstract [en]

Context. The Spectroscopy Made Easy (SME) package has become a popular tool for analyzing stellar spectra, often in connection with large surveys or exoplanet research. SME has evolved significantly since it was first described in 1996, but many of the original caveats and potholes still haunt users. The main drivers for this paper are complexity of the modeling task, the large user community, and the massive effort that has gone into SME.

Aims. We do not intend to give a comprehensive introduction to stellar atmospheres, but will describe changes to key components of SME: the equation of state, opacities, and radiative transfer. We will describe the analysis and fitting procedure and investigate various error sources that affect inferred parameters.

Methods. We review the current status of SME, emphasizing new algorithms and methods. We describe some best practices for using the package, based on lessons learned over two decades of SME usage. We present a new way to assess uncertainties in derived stellar parameters.

Results. Improvements made to SME, better line data, and new model atmospheres yield more realistic stellar spectra, but in many cases systematic errors still dominate over measurement uncertainty. Future enhancements are outlined.

Keyword
stars: abundances, radiative transfer, stars: fundamental parameters, stars: atmospheres, techniques: spectroscopic
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-317615 (URN)10.1051/0004-6361/201629124 (DOI)000392392900084 ()
Available from: 2017-03-16 Created: 2017-03-16 Last updated: 2017-11-29Bibliographically approved
Pakhomov, Y., Piskunov, N. & Ryabchikova, T. (2017). VALD3: Current Developments. In: Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA (Ed.), Stars: From Collapse To Collapse. Paper presented at Conference on Stars: From Collapse to Collapse, Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016 (pp. 518-521). , 510
Open this publication in new window or tab >>VALD3: Current Developments
2017 (English)In: Stars: From Collapse To Collapse / [ed] Balega, YY Kudryavtsev, DO Romanyuk, II Yakunin, IA, 2017, Vol. 510, p. 518-521Conference paper, Published paper (Refereed)
Abstract [en]

Today Vienna Atomic Line Database (VALD) is one of main databases of atomic and molecular parameters required for stellar spectra analysis. We present the new features that recently appeared in the VALD3 release, including the effects of isotopic composition and hyperfine splitting. The latest version of VALD contains parameters for several isotopes of Li, Ca, Ti, Cu, Ba, Eu, and hyperfine splitting of 35 isotopes from Li to Eu.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-347316 (URN)000411770200130 ()978-1-58381-904-3 (ISBN)
Conference
Conference on Stars: From Collapse to Collapse, Special Astrophys Observ, Nizhny Arkhyz, RUSSIA, OCT 03-07, 2016
Available from: 2018-03-29 Created: 2018-03-29 Last updated: 2018-03-29Bibliographically approved
de Jong, R. S., Barden, S. C., Bellido-Tirado, O., Brynnel, J. G., Frey, S., Giannone, D., . . . Starkenburg, E. (2016). 4MOST: the 4-metre Multi-Object Spectroscopic Telescope project at preliminary design review. In: Christopher J Evans (Ed.), GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI: . Paper presented at Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND. , 9908, Article ID UNSP 99081O.
Open this publication in new window or tab >>4MOST: the 4-metre Multi-Object Spectroscopic Telescope project at preliminary design review
Show others...
2016 (English)In: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI / [ed] Christopher J Evans, 2016, Vol. 9908, article id UNSP 99081OConference paper, Published paper (Refereed)
Abstract [en]

We present an overview of the 4MOST project at the Preliminary Design Review. 4MOST is a major new wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of ESO. 4MOST has a broad range of science goals ranging from Galactic Archaeology and stellar physics to the high-energy physics, galaxy evolution, and cosmology. Starting in 2021, 4MOST will deploy 2436 fibres in a 4.1 square degree field-of-view using a positioner based on the tilting spine principle. The fibres will feed one high-resolution (R similar to 20,000) and two medium-resolution (R similar to 5000) spectrographs with fixed 3-channel designs and identical 6k x 6k CCD detectors. 4MOST will have a unique operations concept in which 5-year public surveys from both the consortium and the ESO community will be combined and observed in parallel during each exposure. The 4MOST Facility Simulator (4FS) was developed to demonstrate the feasibility of this observing concept, showing that we can expect to observe more than 25 million objects in each 5-year survey period and will eventually be used to plan and conduct the actual survey.

Series
Proceedings of SPIE, ISSN 0277-786X ; 9908
Keyword
Wide-field multi-object spectrograph facility, VISTA telescope, tilting-spine fibre postioner, wide field corrector, facility simulator, fibre-fed spectrographs, science operations, Gaia, eROSITA, Euclid, PLATO
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-316358 (URN)10.1117/12.2232832 (DOI)000391509100044 ()978-1-5106-0196-3 (ISBN)
Conference
Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND
Available from: 2017-03-06 Created: 2017-03-06 Last updated: 2017-03-06Bibliographically approved
Ryabchikova, T., Piskunov, N., Pakhomov, Y., Tsymbal, V., Titarenko, A., Sitnova, T., . . . Mashonkina, L. (2016). Accuracy of atmospheric parameters of FGK dwarfs determined by spectrum fitting. Monthly notices of the Royal Astronomical Society, 456(2), 1221-1234
Open this publication in new window or tab >>Accuracy of atmospheric parameters of FGK dwarfs determined by spectrum fitting
Show others...
2016 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 456, no 2, p. 1221-1234Article in journal (Refereed) Published
Abstract [en]

We performed extensive tests of the accuracy of atmospheric parameter determination for FGK stars based on the spectrum fitting procedure SpectroscopyMade Easy (SME). Our stellar sample consists of 13 objects, including the Sun, in the temperature range 5000-6600K and metallicity range -1.4-+0.4. The analysed stars have the advantage of having parameters derived by interferometry. For each star, we use spectra obtained with different spectrographs and different signal-to-noise ratios (S/N). For the fitting, we adopted three different sets of constraints and test how the derived parameters depend upon the spectral regions (masks) used in SME. We developed and implemented in SME a new method for estimating uncertainties in the resulting parameters based on fitting residuals, partial derivatives, and data uncertainties. For stars in the 5700-6600K range, the best agreement with the effective temperatures derived by interferometry is achieved when spectrum fitting includes the Ha and H beta lines, while for cooler stars the choice of the mask does not affect the results. The derived atmospheric parameters do not strongly depend on spectral resolution and S/N of the observations, while the uncertainties in temperature and surface gravity increase with increasing effective temperature, with minima at 50K in T-eff and 0.1 dex in log g, for spectra with S/N=150-200. A non-local thermodynamic equilibrium (NLTE) analysis of the Ti I/Ti II and Fe I/Fe II ionization equilibria and abundances determined from the atomic CI (NLTE) and molecular CH species supports the parameters we derived with SME by fitting the observed spectra including the hydrogen lines.

Keyword
methods: data analysis, methods: observational, stars: abundances, stars: fundamental parameters
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-294589 (URN)10.1093/mnras/stv2725 (DOI)000372264200006 ()
Available from: 2016-05-26 Created: 2016-05-25 Last updated: 2017-11-30Bibliographically approved
Follert, R., Taubert, D., Hollandt, J., Monte, C., Oliva, E., Seemann, U., . . . Tordo, S. (2016). Characterizing the cross dispersion reflection gratings of CRIRES. In: Advances In Optical And Mechanical Technologies For Telescopes And Instrumentation Ii: . Paper presented at Conference on Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, JUN 26-JUL 01, 2016, Edinburgh, ENGLAND. , Article ID UNSP 99122B.
Open this publication in new window or tab >>Characterizing the cross dispersion reflection gratings of CRIRES
Show others...
2016 (English)In: Advances In Optical And Mechanical Technologies For Telescopes And Instrumentation Ii, 2016, article id UNSP 99122BConference paper, Published paper (Refereed)
Abstract [en]

The CRIRES+ project attempts to upgrade the CRIRES instrument into a cross dispersed echelle spectrograph with a simultaneous recording of 8-10 diffraction orders. In order to transform the CRIRES spectrograph into a cross-dispersing instrument, a set of six reflection gratings, each one optimized for one of the wavelength bands CRIRES+ will operate in (YJHKLM), will be used as cross dispersion elements in CRIRES+. Due to the upgrade nature of the project, the choice of gratings depends on the fixed geometry of the instrument. Thus, custom made gratings would be required to achieve the ambitious design goals. Custom made gratings have the disadvantage, though, that they come at an extraordinary price and with lead times of more than 12 months. To mitigate this, a set of off-the-shelf gratings was obtained which had grating parameters very close to the ones being identified as optimal. To ensure that the rigorous specifications for CRIRES+ will be fulfilled, the CRIRES+ team started a collaboration with the Physikalisch-Technische Bundesanstalt Berlin (PTB) to characterize gratings under conditions similar to the operating conditions in CRIRES+ (angle of incidence, wavelength range). The respective test setup was designed in collaboration between PTB and the CRIRES+ consortium. The PTB provided optical radiation sources and calibrated detectors for each wavelength range. With this setup, it is possible to measure the absolute efficiency of the gratings both wavelength dependent and polarization state dependent in a wavelength range from 0.9 mu m to 6 mu m.

Series
Proceedings of SPIE, ISSN 0277-786X ; 9912
Keyword
CRIRES+, echelle spectrograph, infrared instrumentation, VLT, diffraction efficiency
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-311408 (URN)10.1117/12.2232569 (DOI)000387747900072 ()9781510602038; 9781510602045 (ISBN)
Conference
Conference on Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, JUN 26-JUL 01, 2016, Edinburgh, ENGLAND
Available from: 2016-12-27 Created: 2016-12-27 Last updated: 2016-12-27Bibliographically approved
Marconi, A., Di Marcantonio, P., D'Odorico, V., Cristiani, S., Maiolino, R., Oliva, E., . . . Zackrisson, E. (2016). EELT-HIRES the high-resolution spectrograph for the E-ELT. In: Christopher J Evans (Ed.), GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI: . Paper presented at Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND. , 9908, Article ID UNSP 990823.
Open this publication in new window or tab >>EELT-HIRES the high-resolution spectrograph for the E-ELT
Show others...
2016 (English)In: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI / [ed] Christopher J Evans, 2016, Vol. 9908, article id UNSP 990823Conference paper, Published paper (Refereed)
Abstract [en]

The first generation of E-ELT instruments will include an optical infrared High Resolution Spectrograph, conventionally indicated as EELT-HIRES, which will be capable of providing unique breakthroughs in the fields of exoplanets, star and planet formation, physics and evolution of stars and galaxies, cosmology and fundamental physics. A 2-year long phase A study for EELT-HIRES has just started and will be performed by a consortium composed of institutes and organisations from Brazil, Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden, Switzerland and United Kingdom. In this paper we describe the science goals and the preliminary technical concept for EELT-HIRES which will be developed during the phase A, as well as its planned development and consortium organisation during the study.

Series
Proceedings of SPIE, ISSN 0277-786X ; 9908
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-316360 (URN)10.1117/12.2231653 (DOI)000391509100058 ()978-1-5106-0196-3 (ISBN)
Conference
Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND
Available from: 2017-03-06 Created: 2017-03-06 Last updated: 2017-03-06Bibliographically approved
Thompson, S. J., Queloz, D., Baraffe, I., Brake, M., Dolgopolov, A., Fisher, M., . . . Young, J. (2016). HARS3 for a Roboticized Isaac Newton Telescope. In: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI: . Paper presented at Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND. , 9908, Article ID UNSP 99086F.
Open this publication in new window or tab >>HARS3 for a Roboticized Isaac Newton Telescope
Show others...
2016 (English)In: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI, 2016, Vol. 9908, article id UNSP 99086FConference paper, Published paper (Refereed)
Abstract [en]

We present a description of a new instrument development, HARPS3, planned to be installed on an upgraded and roboticized Isaac Newton Telescope by end-2018. HARPS3 will be a high resolution (R similar or equal to 115,000) echelle spectrograph with a wavelength range from 380-690 nm. It is being built as part of the Terra Hunting Experiment {a future 10 year radial velocity measurement programme to discover Earth-like exoplanets. The instrument design is based on the successful HARPS spectrograph on the 3.6m ESO telescope and HARPS-N on the TNG telescope. The main changes to the design in HARPS3 will be: a customised fibre adapter at the Cassegrain focus providing a stabilised beam feed and on-sky fibre diameter approximate to 1.4 arcsec, the implementation of a new continuous flow cryostat to keep the CCD temperature very stable, detailed characterisation of the HARPS3 CCD to map the effective pixel positions and thus provide an improved accuracy wavelength solution, an optimised integrated polarimeter and the instrument integrated into a robotic operation. The robotic operation will optimise our programme which requires our target stars to be measured on a nightly basis. We present an overview of the entire project, including a description of our anticipated robotic operation.

Series
Proceedings of SPIE, ISSN 0277-786X ; 9908
Keyword
High resolution spectroscopy, robotic operations, RV measurements, exoplanets
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-316361 (URN)10.1117/12.2232111 (DOI)000391509100184 ()978-1-5106-0196-3 (ISBN)
Conference
Conference on Ground-Based and Airborne Instrumentation for Astronomy VI, JUN 26-30, 2016, Edinburgh, SCOTLAND
Available from: 2017-03-02 Created: 2017-03-02 Last updated: 2017-03-02Bibliographically approved
Organisations

Search in DiVA

Show all publications