Abstrakt
Context. Gaia Data Release 3 (DR3) contains the first release of magnitudes estimated from the integration of Radial Velocity Spectrometer (RVS) spectra for a sample of about 32.2 million stars brighter than G(RVS) similar to 14 mag (or G similar to 15 mag).
Aims. In this paper, we describe the data used and the approach adopted to derive and validate the GRVS magnitudes published in DR3.
We also provide estimates of the G(RVS) passband and associated GRVS zero-point. Methods.
We derived G(RVS) photometry from the integration of RVS spectra over the wavelength range from 846 to 870 nm. We processed these spectra following a procedure similar to that used for DR2, but incorporating several improvements that allow a better estimation of G(RVS).
These improvements pertain to the stray-light background estimation, the line spread function calibration, and the detection of spectra contaminated by nearby relatively bright sources. We calibrated the G(RVS) zero-point every 30 h based on the reference magnitudes of constant stars from the Hipparcos catalogue, and used them to transform the integrated flux of the cleaned and calibrated spectra into epoch magnitudes.
The G(RVS) magnitude of a star published in DR3 is the median of the epoch magnitudes for that star. We estimated the G(RVS) passband by comparing the RVS spectra of 108 bright stars with their flux-calibrated spectra from external spectrophotometric libraries.
Results. The G(RVS) magnitude provides information that is complementary to that obtained from the G, G(BP), and G(RP) magnitudes, which is useful for constraining stellar metallicity and interstellar extinction.
The median precision of G(RVS) measurements ranges from about 0.006 mag for the brighter stars (i.e. with 3:5 less than or similar to G(RVS) less than or similar to 6:5 mag) to 0.125 mag at the faint end. The derived G(RVS) passband shows that the effective transmittance of the RVS is approximately 1.23 times better than the pre-launch estimate.