The catalog of radial velocity standard stars for the Gaia RVS: status and progress of the observations

TL;DR

This paper reports on the development of a comprehensive sky-wide catalog of stable radial velocity standard stars for Gaia's RVS instrument, detailing the selection, observation, and calibration processes to ensure measurement accuracy.

Contribution

It presents the ongoing progress and methodology of building a stable radial velocity standard star catalog for Gaia, including multi-instrument calibration and candidate validation.

Findings

Approximately 8% of candidates are rejected due to variability.

Use of multiple spectrographs and archives for calibration.

Progress in verifying candidate stability over several years.

Abstract

A new full-sky catalog of Radial Velocity standard stars is being built for the determination of the Radial Velocity Zero Point of the RVS on board of Gaia. After a careful selection of 1420 candidates matching well defined criteria, we are now observing all of them to verify that they are stable enough over several years to be qualified as reference stars. We present the status of this long-term observing programme on three spectrographs : SOPHIE, NARVAL and CORALIE, complemented by the ELODIE and HARPS archives. Because each instrument has its own zero-point, we observe intensively IAU RV standards and asteroids to homogenize the radial velocity measurements. We can already estimate that ~8% of the candidates have to be rejected because of variations larger than the requested level of 300 m/s.