The X-ray Continuum Slope of Quasars

被引:0
|
作者
Scott, A. [1 ]
Stewart, G. [1 ]
Mateos, S. [1 ]
Alexander, D. [2 ]
Hutton, S. [2 ]
机构
[1] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England
[2] Univ Durham, Dept Phys, Durham DH1 3LE, England
关键词
X-rays:spectra; galaxies:active; 5TH DATA RELEASE;
D O I
10.1063/1.3475324
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the X-ray properties of a large, optically selected sample of quasars from a cross-correlation of the SDSS DR5 quasar catalogue and the X-ray serendipitous source catalogue 2XMMi. We consider the dependence of photon index on X-ray luminosity and redshift. We find evidence for a correlation of photon index and redshift (decreasing photon indices for higher redshift sources) and propose that this may be due to a Compton reflection component being redshifted into the XMM-Newton observed energy band. We show that this apparent trend can be removed when the spectra are analysed over a reduced range that would exclude any contribution from such a reflection component.
引用
收藏
页码:509 / +
页数:2
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