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

Abstract

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 AGN 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 NeXT and Simbol-X that can image such sources as well as confirm the precise spectral shape of the background near its peak, important for constraining the universal relevance of light bending.

15 pages, 13 figures. MNRAS accepted

References in corpus (66)

• Local Supermassive Black Holes, Relics of Active Galactic Nuclei and the X-ray Background
• An Observational Determination of the Bolometric Quasar Luminosity Function
• Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• The distribution of absorbing column densities among Seyfert 2 galaxies
• A light bending model for the X-ray temporal and spectral properties of accreting black holes
• Piecing Together the X-ray Background: Bolometric Corrections for Active Galactic Nuclei
• An Explanation for the soft X-ray excess in AGN
• Deep Extragalactic X-ray Surveys
• The Cosmic Evolution of Hard X-ray Selected Active Galactic Nuclei
• The HELLAS2XMM survey. VII. The hard X-ray luminosity function of AGN up to z=4: more absorbed AGN at low luminosities and high redshifts
• Elemental Abundances in QSOs: Star Formation and Galactic Nuclear Evolution at High Redshifts
• X-ray Spectra of a large sample of Quasars with ASCA
• The Spectrum of Diffuse Cosmic Hard X-Rays Measured with HEAO-1
• Dust in active nuclei. I. Evidence for "anomalous" properties
• X-ray spectral properties of AGN in the Chandra Deep Field South
• A long hard look at MCG-6-30-15 with XMM-Newton
• The distribution and cosmic evolution of massive black hole spins
• The Contribution of the Obscuring Torus to the X--Ray Spectrum of Seyfert Galaxies: A Test for the Unification Model
• Extreme X-ray spectral variability in the Seyfert 2 Galaxy NGC 1365
• The mass density in black holes inferred from the X-ray background
• Most Supermassive Black Holes must be Rapidly Rotating
• Thermal Instability and Photoionized X-ray Reflection in Accretion Disks
• The Nature of the Hard X-ray Background Sources: Optical, Near-infrared, Submillimeter, and Radio Properties
• INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth
• Testing current synthesis models of the X-ray background
• Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes
• The iron line in MCG-6-30-15 from XMM-Newton: evidence for gravitational light-bending?
• X-ray reflection in the NLS1 1H 0707-495
• Suzaku observations of the hard X-ray variability of MCG-6-30-15: the effects of strong gravity around a Kerr black hole
• XMM-Newton study of the complex and variable spectrum of NGC 4051
• Hard X-ray luminosity function and absorption distribution of nearby AGN: INTEGRAL all-sky survey
• Evidence for Black Hole Spin in GX 339-4: XMM-Newton EPIC-pn and RXTE Spectroscopy of the Very High State
• The Swift/BAT High Latitude Survey: First Results
• The Relativistic Fe Emission Line in XTE J1650-500 with BeppoSAX: Evidence for Black Hole Spin and Light Bending Effects?
• The XMM-Newton wide-field survey in the COSMOS field. IV: X-ray spectral properties of Active Galactic Nuclei
• The HELLAS2XMM survey: VI. X-ray absorption in the 1dfAGN sample through a spectral analysis
• Connecting Galaxy Evolution, Star Formation and the X-ray Background
• XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN
• Hard X-ray emitting Active Galactic Nuclei selected by the Chandra Multi-wavelength Project
• The First INTEGRAL AGN Catalog
• X-ray reflection in the Seyfert galaxy 1H0419-577 revealing strong relativistic effects in the vicinity of a Kerr black hole
• The cosmic X-ray background and the population of the most heavily obscured AGNs
• Evidence for Rapidly Spinning Black Holes in Quasars
• X-ray background synthesis: the infrared connection
• The growth of the nuclear black holes in submillimeter galaxies
• Fitting the spectrum of the X-ray background: the effects of high metallicity absorption
• X-ray spectra of XMM-Newton serendipitous medium flux sources
• Iron-line and continuum flux variations in the RXTE spectra of the black-hole candidate XTE J1650-500
• The distribution of absorption in AGN detected in the XMM-Newton observations of the CDFS
• Statistics of relativistically broadened Fe K-alpha lines in AGN
• X-ray lighthouses of the high-redshift Universe. Probing the most luminous z>4 Palomar Digital Sky Survey Quasars with Chandra
• An XMM-Newton Study of the Hard X-ray Sky
• On the X-ray spectra of luminous, inhomogeneous accretion flows
• On the intensity of the cosmic X-ray background
• Intensity of the cosmic X-ray backgound from HEAO1/A2 experiment
• X-ray spectra of sources in the 13H XMM-Newton / Chandra deep field
• IRAS 13197-1627 has them all: Compton-thin absorption, photo-ionized gas, thermal plasmas, and a broad Fe line
• Can the unresolved X-ray background be explained by emission from the optically-detected faint galaxies of the GOODS project?
• ASCA observations of the Seyfert 1 galaxies Mrk1040 and MS0225.5+3121
• INTEGRAL observations of AGN obscured by the Galactic Plane
• Gravitational effects on the high energy emission of accreting black holes
• The 1 keV to 200 keV X-ray Spectrum of NGC 2992 and NGC 3081
• Growth of massive black holes during radiatively inefficient accretion phases
• On the Origin of the Hard X-Ray Background
• On the fraction of X-ray obscured quasars in the local universe

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