Redshift evolution of X-ray spectral index of quasars observed by XMM-NEWTON/SDSS

被引：4

作者：

Shehata, Sh M. ^{[1
]}

Misra, R. ^{[2
]}

Osman, A. M., I ^{[1
]}

Shalabiea, O. M. ^{[3
,4
]}

Hayman, Z. M. ^{[3
]}

机构：

[1] Natl Res Inst Astron & Geophys, Cairo 11421, Egypt

[2] Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India

[3] Cairo Univ, Fac Sci, Astron Space Sci & Meteorol Dept, Giza, Egypt

[4] Beni Suef Univ, Fac Nav Sci & Space Technol, Bani Suwayf, Egypt

来源：

JOURNAL OF HIGH ENERGY ASTROPHYSICS | 2021年 / 31卷

基金：

美国国家科学基金会;

关键词：

Quasars; General; X-rays; ACTIVE GALACTIC NUCLEI; BAND ENERGY-DISTRIBUTION; ROSAT DETECTED QUASARS; RADIO-QUIET; CHANDRA OBSERVATIONS; EMISSION; LOUD; HARD;

D O I：

10.1016/j.jheap.2021.04.003

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We study the X-ray spectral evolution of quasars with red-shift using a sample of 1280 quasars constructed by cross-referencing the XMM-Newton 3XMM - DR7 and the optical SDSS-DR14 catalogues. The sources were selected to have a minimum detected X-ray counts > 600 and which were not affected by high background. The sample redshift distribution ranges from 0-4.9 and peaks around 1. For each source, the XMM-Newton EPIC_PN spectra were generated and fitted with a power-law model with Galactic absorption. Consistent with some earlier results we find a strong correlation between the photon index and redshift. We explicitly test the hypothesis that this is due to the X-ray soft excess and reflection bump being red-shifted away from the XMM band, by adding a black body and reflection component and find that the correlation is no longer significant. Thus, for the first time, we show that there is no evidence for quasar spectral evolution and the correlation between index and red-shift is indeed due to the soft excess and reflection component. (C) 2021 Elsevier B.V. All rights reserved.

引用

页码：37 / 43

页数：7

共 36 条

[1] Chandra survey of radio-quiet, high-redshift quasars [J].

Bechtold, J ;

Siemiginowska, A ;

Shields, J ;

Czerny, B ;

Janiuk, A ;

Hamann, F ;

Aldcroft, TL ;

Elvis, M ;

Dobrzycki, A .

ASTROPHYSICAL JOURNAL, 2003, 588 (01) :119-127

[2] Exploratory Chandra observations of the three highest redshift quasars known [J].

Brandt, WN ;

Schneider, DP ;

Fan, XH ;

Strauss, MA ;

Gunn, JE ;

Richards, GT ;

Anderson, SF ;

Vanden Berk, DE ;

Bahcall, NA ;

Brinkmann, J ;

Brunner, R ;

Chen, B ;

Hennessy, GS ;

Lamb, DQ ;

Voges, W ;

York, DG .

ASTROPHYSICAL JOURNAL, 2002, 569 (01) :L5-L9

[3] A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys [J].

Brightman, M. ;

Silverman, J. D. ;

Mainieri, V. ;

Ueda, Y. ;

Schramm, M. ;

Matsuoka, K. ;

Nagao, T. ;

Steinhardt, C. ;

Kartaltepe, J. ;

Sanders, D. B. ;

Treister, E. ;

Shemmer, O. ;

Brandt, W. N. ;

Brusa, M. ;

Comastri, A. ;

Ho, L. C. ;

Lanzuisi, G. ;

Lusso, E. ;

Nandra, K. ;

Salvato, M. ;

Zamorani, G. ;

Akiyama, M. ;

Alexander, D. M. ;

Bongiorno, A. ;

Capak, P. ;

Civano, F. ;

Del Moro, A. ;

Doi, A. ;

Elvis, M. ;

Hasinger, G. ;

Laird, E. S. ;

Masters, D. ;

Mignoli, M. ;

Ohta, K. ;

Schawinski, K. ;

Taniguchi, Y. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2013, 433 (03) :2485-2496

[4]

Brinkmann W, 1997, ASTRON ASTROPHYS, V319, P413

[5]

CASH W, 1979, ASTROPHYS J, V228, P939, DOI 10.1086/156922

[6] Soft versus hard X-ray emission in active galactic nuclei: Partial covering and warm-plus-cold absorber models [J].

Ceballos, MT ;

Barcons, X .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1996, 282 (02) :493-500

[7]

DOnofrio M., 2012, Astrophysics and Space Science Library, V386

[8] ATLAS OF QUASAR ENERGY-DISTRIBUTIONS [J].

ELVIS, M ;

WILKES, BJ ;

MCDOWELL, JC ;

GREEN, RF ;

BECHTOLD, J ;

WILLNER, SP ;

OEY, MS ;

POLOMSKI, E ;

CUTRI, R .

ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1994, 95 (01) :1-68

[9] A long hard look at MCG-6-30-15 with XMM-Newton [J].

Fabian, AC ;

Vaughan, S ;

Nandra, K ;

Iwasawa, K ;

Ballantyne, DR ;

Lee, JC ;

De Rosa, A ;

Turner, A ;

Young, AJ .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2002, 335 (01) :L1-L5

[10] Properties of radio-loud quasars in the Sloan Digital Sky Survey [J].

Gaur, H. ;

Gu, M. ;

Ramya, S. ;

Guo, H. .

ASTRONOMY & ASTROPHYSICS, 2019, 631

← 1 2 3 4 →