VizieR Online Data Catalog: Stellar content of the ROSAT all-sky survey (Freund+, 2022)

We present the stellar content of the ROSAT all-sky survey (RASS), which was identified by a crossmatch between the RASS sources and eligible stellar counterparts from Gaia EDR3. The main catalog contains counterparts to the 115000 RASS sources with the best positional accuracy. The identifications to the remaining sources are listed in the supplementary catalog, but for these sources our identification procedure is less reliable. The catalogs contain the names of the RASS sources and the stellar matches (Gaia source ID or Tycho2 ID if the source is not available in Gaia EDR3), the corrected positional uncertainties of the RASS sources, the angular separations between the RASS sources and the stellar identifications, the proper motion corrected Gaia positions at the RASS observation time, and basic properties. Sources located more than 1.5mag below the main sequence are flagged as a subdwarf and are probably the correct identification but the X-ray emission is not produced by a solar-like corona. Furthermore, we provide stellar (p_stellar) and matching probabilities (p_ij) to the RASS sources and the individual counterparts. These probabilities are estimated with a Bayesian framework that is based on a training set of sources with a good geometric match. In the training catalog, the counterparts with high geometric probabilities (p_geo>0.9) are specified and sources that are unlikely to be coronal emitters are flagged. Note that we adopted only the unflagged sources for our training set. The main and supplementary catalogs contain all stellar counterparts with a matching probability p_ij>0.1 to the RASS sources with a stellar probability p_stellar>0.2. RASS sources with multiple counterparts have several entries in the catalog. For the discussion of the properties of the stellar RASS sources, we adopted the counterparts with p_stellar>0.51 and p_ij>0.5 of the main catalog that are not flagged as a subdwarf.

(3 data files).