Spectroscopic survey of the Galaxy with Gaia- I. Design and performance of the Radial Velocity Spectrometer

D. Katz (1) , U. Munari (2) , M. Cropper (3) , T. Zwitter (4) , F. Thévenin (5) , M. David (6) , Y. Viala (1) , F. Crifo (1) , A. Gomboc (7) , F. Royer (1) , Frédéric Arenou (1) , P. Marrese (2) , R. Sordo (2) , M. Wilkinson , A. Vallenari (2) , C. Turon (1) , A. Helmi (8) , Guillaume Bono , M. Perryman (9) , A. Gomez (10) , L. Tomasella (2) , F. Boschi (2) , D. Morin (1) , M. Haywood (1) , C. Soubiran (11) , F. Castelli (12) , A. Bijaoui (5) , G. Bertelli (2) , A. Prsa (4) , S. Mignot (1) , Alain Sellier (1) , M-O Baylac (13) , Y. Lebreton (1) , U. Jauregi (4) , A. Siviero (2) , R. Bingham (14) , F. Chemla (1) , J. Coker (3) , T. Dibbens (3) , B. Hancock (3) , A. Holland (15) , D. Horville (1) , J-M Huet (13) , P. Laporte (16) , T. Melse (1) , F. Sayede (1) , T-J Stevenson (15) , P. Vola (1) , D. Walton (3) , B. Winter (3)

1 GEPI - Galaxies, Etoiles, Physique, Instrumentation
2 OAPD - INAF - Osservatorio Astronomico di Padova
3 MSSL - Mullard Space Science Laboratory
4 University of Ljubljana
5 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides
6 Universiteit Antwerpen = University of Antwerpen [Antwerpen]
7 FMF - Faculty of Mathematics and Physics [Ljubljana]
8 Kapteyn Astronomical Institute [Groningen]
9 ESTEC - European Space Research and Technology Centre
10 OAR - INAF - Osservatorio Astronomico di Roma
11 OASU - Observatoire aquitain des sciences de l'univers
12 OAT - INAF - Osservatorio Astronomico di Trieste
13 OP - Observatoire de Paris - Site de Paris
14 Rutheford Appleton Laboratory
15 University of Leicester
16 LHC - Laboratoire Hubert Curien

The definition and optimization studies for the Gaia satellite spectrograph, the 'radial velocity spectrometer' (RVS), converged in late 2002 with the adoption of the instrument baseline. This paper reviews the characteristics of the selected configuration and presents its expected performance. The RVS is a 2.0 × 1.6 degree integral field spectrograph, dispersing the light of all sources entering its field of view with a resolving power R = λ//λ = 11 500 over the wavelength range [848, 874] nm. The RVS will continuously and repeatedly scan the sky during the 5-yr Gaia mission. On average, each source will be observed 102 times over this period. The RVS will collect the spectra of about 100-150 million stars up to magnitude V 17-18. At the end of the mission, the RVS will provide radial velocities with precisions of ∼2 km s −1 at V = 15 and ∼15-20 km s −1 at V = 17, for a solar-metallicity G5 dwarf. The RVS will also provide rotational velocities, with precisions (at the end of the mission) for late-type stars of σ v sin i 5 km s −1 at V 15 as well as atmospheric parameters up to V 14-15. The individual abundances of elements such as silicon and magnesium, vital for the understanding of Galactic evolution, will be obtained up to V 12-13. Finally, the presence of the 862.0-nm

Mots clés: instrumentation: spectrographs; techniques: radial velocities; space vehicles: instruments; techniques: spectroscopic

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]; Astrophysique galactique [astro-ph.GA]

D. Katz, U. Munari, M. Cropper, T. Zwitter, F. Thévenin, et al.. Spectroscopic survey of the Galaxy with Gaia- I. Design and performance of the Radial Velocity Spectrometer. Monthly Notices of the Royal Astronomical Society, 2004, 354 (4), pp.1223-1238. ⟨10.1111/j.1365-2966.2004.08282.x⟩. ⟨hal-02053985⟩