NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2018-12-16 T08:21:25 PST
Help | Comment | NED Home

For refcode 2009ApJS..183...17Y:
Retrieve 792 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2009ApJS..183...17Y The Fifth Data Release Sloan Digital Sky Survey/XMM-Newton Quasar Survey Young, M.; Elvis, M.; Risaliti, G. Abstract. We present a catalog of 792 Fifth Data Release Sloan Digital Sky Survey quasars with optical spectra that have been observed serendipitously in the X-rays with the XMM-Newton. These quasars cover a redshift range of z = 0.11-5.41 and a magnitude range of i = 15.3-20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at >=2{sigma} account for 87% of the sample (685 quasars), and 473 quasars are detected at >=6{sigma}, sufficient to allow X-ray spectral fits. For detected sources, ~60% have X-ray fluxes between F_2-10 keV_ = (1-10) x10^-14^ erg cm^-2^ s^-1^. We fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio >= 6, resulting in a weighted mean photon index Gamma = 1.91 +/- 0.08, with an intrinsic dispersion {sigma}_Gamma_ = 0.38. For the 55 sources (11.6%) that prefer intrinsic absorption, we find a weighted mean N_H_ = 1.5 +/- 0.3 x 10^21^ cm^-2^. We find that Gamma correlates significantly with optical color, {DELTA}(g - i), the optical-to-X-ray spectral index ({alpha}_ox_), and the X-ray luminosity. While the first two correlations can be explained as artifacts of undetected intrinsic absorption, the correlation between Gamma and X-ray luminosity appears to be a real physical correlation, indicating a pivot in the X-ray slope. Key words: accretion, accretion disks, quasars: general =========================================================================== 2009ApJS..185..250Y ERRATUM: "The Fifth Data Release Sloan Digital Sky Survey/XMM-Newton Quasar Survey" (2009, ApJS, 183, 17) Young, M.; Elvis, M.; Risaliti, G. Abstract. We have discovered an error in Column 9 of Table 2 in the original paper. This column reports the fit flags, indicating which model a source prefers: a simple power-law (SPL; flag = 1), a fixed power-law plus intrinsic absorption (FPL; flag = 2), or an absorbed power-law (APL; flag = 3). The table of the original paper mistakenly reports all flag = 3 sources as having flag = 2, and all flag = 2 sources as having flag = 1, so that only 32 sources prefer an absorption model. We have updated Table 2 to print out the correct fit flags for each source, resulting in 55 sources that prefer an absorption model. Since the fit flags determine which numbers are reported for the remaining columns of Table 2, these numbers are updated as well. The abstract and text of the original paper report the correct number of absorbed sources, so the conclusions are unaffected. In addition, a minor rounding error was found in the SDSS names of some objects, and so we replace both Tables 1 and 2 with corrected versions. ===========================================================================
Retrieve 792 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home