Article (Scientific journals)
The Gaia astrophysical parameters inference system (Apsis). Pre-launch description
Bailer-Jones, C. A. L.; Andrae, R.; Arcay, B. et al.
2013In Astronomy and Astrophysics, 559, p. 74
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Keywords :
Astrophysics - Instrumentation and Methods for Astrophysics; Astrophysics - Galaxy Astrophysics; Astrophysics - Solar and Stellar Astrophysics
Abstract :
[en] The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred million stars. Its main objective is to take a census of the stellar content of our Galaxy, with the goal of revealing its formation and evolution. Gaia's unique feature is the measurement of parallaxes and proper motions with hitherto unparalleled accuracy for many objects. As a survey, the physical properties of most of these objects are unknown. Here we describe the data analysis system put together by the Gaia consortium to classify these objects and to infer their astrophysical properties using the satellite's data. This system covers single stars, (unresolved) binary stars, quasars, and galaxies, all covering a wide parameter space. Multiple methods are used for many types of stars, producing multiple results for the end user according to different models and assumptions. Prior to its application to real Gaia data the accuracy of these methods cannot be assessed definitively. But as an example of the current performance, we can attain internal accuracies (RMS residuals) on F,G,K,M dwarfs and giants at G=15 (V=15-17) for a wide range of metallicites and interstellar extinctions of around 100K in effective temperature (Teff), 0.1mag in extinction (A0), 0.2dex in metallicity ([Fe/H]), and 0.25dex in surface gravity (logg). The accuracy is a strong function of the parameters themselves, varying by a factor of more than two up or down over this parameter range. After its launch in November 2013, Gaia will nominally observe for five years, during which the system we describe will continue to evolve in light of experience with the real data.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Bailer-Jones, C. A. L.
Andrae, R.
Arcay, B.
Astraatmadja, T.
Bellas-Velidis, I.
Berihuete, A.
Bijaoui, A.
Carrión, C.
Dafonte, C.
Damerdji, Yassine ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Dapergolas, A.
de Laverny, P.
Delchambre, Ludovic  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Drazinos, P.
Drimmel, R.
Frémat, Y.
Fustes, D.
García-Torres, M.
Guédé, C.
Heiter, U.
Janotto, A.-M.
Karampelas, A.
Kim, D.-W.
Knude, J.
Kolka, I.
Kontizas, E.
Kontizas, M.
Korn, A. J.
Lanzafame, A. C.
Lebreton, Y.
Lindstrøm, H.
Liu, C.
Livanou, E.
Lobel, A.
Martayan, C.
Ordenovic, Ch
Pichon, B.
Recio-Blanco, A.
Rocca-Volmerange, B.
Sarro, L. M.
Smith, K.
Sordo, R.
Soubiran, C.
Surdej, Jean  ;  Université de Liège - ULiège > AGO > Astroph. extragalactique et observations spatiales (AEOS)
Thévenin, F.
Tsalmantza, P.
Vallenari, A.
Zorec, J.
More authors (38 more) Less
Language :
English
Title :
The Gaia astrophysical parameters inference system (Apsis). Pre-launch description
Publication date :
01 November 2013
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
559
Pages :
A74
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
21 pages, accepted to A&A
Available on ORBi :
since 21 November 2013

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