Constraints on light bending and reflection from the hard X-ray background

被引:32
作者
Gandhi, P. [1 ,2 ]
Fabian, A. C. [2 ]
Suebsuwong, T. [3 ,4 ]
Malzac, J. [3 ]
Miniutti, G. [2 ]
Wilman, R. J. [5 ]
机构
[1] RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan
[2] Inst Astron, Cambridge CB3 0HA, England
[3] Ctr Etud Spatiale Rayonnements, F-31208 Toulouse, France
[4] Kasetsart Univ, Fac Engn, Dept Aerosp Engn, Bangkok, Thailand
[5] Univ Oxford, Oxford OX1 3RH, England
关键词
galaxies; active; X-rays;
D O I
10.1111/j.1365-2966.2007.12462.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Light bending due to strong gravity has recently been invoked to explain variability and flux correlations between different bands in some accreting black holes. A characteristic feature of light bending is reflection-dominated spectra, especially if photon sources lie in the deepest parts of the gravitational potential within a few gravitational radii of the event horizon. We use the spectrum of the hard X-ray background in order to constrain the prevalence of such reflection-dominated sources. We first emphasize the need for reflection and explore the broad-band properties of realistic spectra that incorporate light bending. We then use these spectra, in conjunction with the observed 2-10 keV active galactic nucleus distribution, evolutionary and obscuration functions in order to predict the hard X-ray background spectrum over 3-100 keV, and provide limits on the fraction of reflection-dominated objects, dependent on the height of the photon sources. Our results allow for a cosmologically-significant fraction of sources that incorporate strong light bending. The luminosity function based on intrinsic flare luminosities is derived and implications discussed. We discuss prospects for future hard X-ray missions such as New X-ray Telescope/Non-thermal Energy eXploration Telescope and Simbol-X that can image such sources as well as confirm the precise spectral shape of the X-ray background near its peak, important for constraining the universal relevance of light bending.
引用
收藏
页码:1005 / 1018
页数:14
相关论文
共 93 条
[31]   THE CONTRIBUTION OF THE OBSCURING TORUS TO THE X-RAY-SPECTRUM OF SEYFERT-GALAXIES - A TEST FOR THE UNIFICATION MODEL [J].
GHISELLINI, G ;
HAARDT, F ;
MATT, G .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1994, 267 (03) :743-754
[32]   The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era [J].
Gilli, R. ;
Comastri, A. ;
Hasinger, G. .
ASTRONOMY & ASTROPHYSICS, 2007, 463 (01) :79-96
[33]   Testing current synthesis models of the X-ray background [J].
Gilli, R ;
Salvati, M ;
Hasinger, G .
ASTRONOMY & ASTROPHYSICS, 2001, 366 (02) :407-417
[34]   The growth of the nuclear black holes in submillimetre galaxies [J].
Granato, GL ;
Silva, L ;
Lapi, A ;
Shankar, F ;
De Zotti, G ;
Danese, L .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2006, 368 (01) :L72-L76
[35]   The spectrum of diffuse cosmic hard X-rays measured with HEAO 1 [J].
Gruber, DE ;
Matteson, JL ;
Peterson, LE ;
Jung, GV .
ASTROPHYSICAL JOURNAL, 1999, 520 (01) :124-129
[36]   Statistics of relativistically broadened FeKα lines in AGN [J].
Guainazzi, M. ;
Bianchi, S. ;
Dovciak, M. .
ASTRONOMISCHE NACHRICHTEN, 2006, 327 (10) :1032-1038
[37]   On the transmission-dominated to reprocessing-dominated spectral state transitions in Seyfert 2 galaxies [J].
Guainazzi, M ;
Fabian, AC ;
Iwasawa, K ;
Matt, G ;
Fiore, F .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2005, 356 (01) :295-308
[38]   Elemental abundances in quasistellar objects: Star formation and galactic nuclear evolution at high redshifts [J].
Hamann, F ;
Ferland, G .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1999, 37 :487-531
[39]   An observational determination of the bolometric quasar luminosity function [J].
Hopkins, Philip F. ;
Richards, Gordon T. ;
Hernquist, Lars .
ASTROPHYSICAL JOURNAL, 2007, 654 (02) :731-753
[40]   THE X-RAY BALDWIN EFFECT [J].
IWASAWA, K ;
TANIGUCHI, Y .
ASTROPHYSICAL JOURNAL, 1993, 413 (01) :L15-L18