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A. A. Suchkov (Rockland Hill Astro Lab, LLC), R. J. Hanisch (STScI), W. Voges (Max Plank Institute)
We present a catalog of 1720 SDSS DR4 spectroscopically identified quasars for which we find high probability cross-matches in the White-Giommi-Angelini catalog (WGACAT; http://wgacat.gsfc.nasa.gov) of ROSAT PSPC pointed observations. Of these objects, only 336 (19.5%) were previously identified in WGACAT as QSO or AGN and the remainder are new identifications. Independent classification of these sources using the ClassX X-ray classifier (http://heasarc.gsfc.nasa.gov/classx; McGlynn et al. 2004, ApJ, 616,1284) indicates that over 80% of the objects should be quasars or AGN. This catalog, therefore, increases the number of known X-ray emitting quasars in the WGACAT by a factor of five.
The catalog has potentially important implications for the study of obscured AGN and evolutionary models for QSOs. Indeed, preliminary analysis suggests that we can identify a significant number of obscured AGN, further augmenting the study of Padovani et al. (2005, A&A, 424, 545) in which such objects were detected using the Virtual Observatory. We can also identify various trends in the redshift dependence of the X-ray and optical parameters, which can provide further insights into the cosmological evolution of QSOs.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.