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arXiv · 0809.1058

A Full Year's Chandra Exposure on SDSS Quasars from the Chandra Multiwavelength Project

Paul J. Green·T. L. Aldcroft·G. T. Richards·W. A. Barkhouse·A. Constantin·D. Haggard·M. Karovska·D. -W. Kim·M. Kim·A. Vikhlinin·A. Mossman·J. D. Silverman·S. F. Anderson·V. Kashyap·B. J. Wilkes·H. Tananbaum
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Abstract

We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey (SDSS) that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project (ChaMP). Our highest-confidence matched sample includes 1135 X-ray detected quasars in the redshift range 0.2 3 QSOs detected, we find no evidence for evolution out to z~5 for either the X-ray photon index Gamma or for the ratio of optical/UV to X-ray flux alpha_ox. About 10% of detected QSOs are obscured (Nh>1E22), but the fraction might reach ~1/3 if most non-detections are absorbed. We confirm a significant correlation between alpha_ox and optical luminosity, but it flattens or disappears for fainter AGN alone. Gamma hardens significantly both towards higher X-ray luminosity, and for relatively X-ray loud quasars. These trends may represent a relative increase in non-thermal X-ray emission, and our findings thereby strengthen analogies between Galactic black hole binaries and AGN.

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Paul J. Green, T. L. Aldcroft, G. T. Richards, W. A. Barkhouse, A. Constantin, D. Haggard, M. Karovska, D. -W. Kim, M. Kim, A. Vikhlinin, A. Mossman, J. D. Silverman, S. F. Anderson, V. Kashyap, B. J. Wilkes, H. Tananbaum. 2008-09-05. A Full Year's Chandra Exposure on SDSS Quasars from the Chandra Multiwavelength Project. https://doi.org/10.1088/0004-637x%2F690%2F1%2F644

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