X-ray emission from radio-quiet quasars in the Sloan Digital Sky Survey Early Data Release: The αOX dependence upon ultraviolet luminosity

摘要: We investigate the X-ray properties of color-selected, radio-quiet quasars (RQQs) in Sloan Digital Sky Survey (SDSS) Early Data Release using ROSAT, Chandra, and XMM-Newton data. In 0.16–6.28 redshift range, 136 RQQs have detections (69 from ROSAT All-Sky Survey, RASS), while for 70 upper limits are obtained. The well-defined selection method used by SDSS, coupled with tight radio constraints FIRST NVSS surveys, allows us to define a representative sample optically selected whose broadband spectral energy distributions (characterized means optical–to–X-ray index, αox) can be studied as function rest-frame ultraviolet (UV) luminosity redshift. A partial correlation analysis applied SDSS (including limits, but excluding biased subsample RASS detections) shows that αox is UV (i.e., steepens at high luminosities); this significant 3.7 σ level. do not detect highly dependence αox. also find (7.8 level) between luminosity. This correlation, parameterized LX ∝ L, extends previous results highest redshifts.