ROSAT All-Sky Survey and SDSS Sample of X-Ray Emitting Stars

The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. The authors use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g > 15<sup>mag</sup>). Instead, the authors use SDSS photometry, correlations with the Two Micron All Sky Survey (2MASS) and other catalogs, and spectroscopy from the Apache Point Observatory 3.5 m telescope to identify these stellar X-ray counterparts. Their sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. The authors derive distances to these stars using photometric parallax relations appropriate for dwarfs on the main sequence, and use these distances to calculate their X-ray luminosities L<sub>X</sub>. They also identify a previously unknown cataclysmic variable (CV) as a RASS counterpart. Much more information on the SDSS is available at the project's web site at <a href="http://www.sdss.org/">http://www.sdss.org/</a>;. This table was created by the HEASARC in April 2009 based on the the machine-readable version of Table 4 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/nasa.heasarc/rassdsstar
Related Identifier https://heasarc.gsfc.nasa.gov/W3Browse/all/rassdsstar.html
Related Identifier https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_rassdsstar&Action=More+Options&Action=Parameter+Search&ConeAdd=1
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://nasa.heasarc/rassdsstar
Provenance
Creator Agueros et al.
Publisher NASA/GSFC HEASARC
Publication Year 2025
OpenAccess true
Contact NASA/GSFC HEASARC help desk <heasarc-vo at athena.gsfc.nasa.gov>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy