Gaia Data Release 3: Hot-star radial velocities
Abstract
The second Gaia data release, DR2, contained radial velocities of stars with effective temperatures up to Teff = 6900 K. The third data release, Gaia DR3, extends this up to Teff = 14,500 K. We derive the radial velocities for hot stars (i.e. in the Teff = 6900 - 14,500 K range) from data obtained with the Radial Velocity Spectrometer (RVS) on board Gaia. The radial velocities were determined by the standard technique of measuring the Doppler shift of a template spectrum that was compared to the observed spectrum. The RVS wavelength range is very limited. The proximity to and systematic blueward offset of the calcium infrared triplet to the hydrogen Paschen lines in hot stars can result in a systematic offset in radial velocity. For the hot stars, we developed a specific code to improve the selection of the template spectrum, thereby avoiding this systematic offset. With the improved code, and with the correction we propose to the DR3 archive radial velocities, we obtain values that agree with reference values to within 3 km/s (in median). Because of the required S/N for applying the improved code, the hot star radial velocities in DR3 are mostly limited to stars with a magnitude in the RVS wavelength band <= 12 mag.
Cite
@article{arxiv.2206.05486,
title = {Gaia Data Release 3: Hot-star radial velocities},
author = {R. Blomme and Y. Fremat and P. Sartoretti and A. Guerrier and P. Panuzzo and D. Katz and G. M. Seabroke and F. Thevenin and M. Cropper and K. Benson and Y. Damerdji and R. Haigron and O. Marchal and M. Smith and S. Baker and L. Chemin and M. David and C. Dolding and E. Gosset and K. Janssen and G. Jasniewicz and A. Lobel and G. Plum and N. Samaras and O. Snaith and C. Soubiran and O. Vanel and T. Zwitter and N. Brouillet and E. Caffau and F. Crifo and C. Fabre and F. Frakgoudi and H. E. Huckle and A. Jean-Antoine Piccolo and Y. Lasne and N. Leclerc and A. Mastrobuono-Battisti and F. Royer and Y. Viala and J. Zorec},
journal= {arXiv preprint arXiv:2206.05486},
year = {2023}
}
Comments
12 pages, 11 figures, accepted by A&A for Gaia Special Issue