Book contents
- Frontmatter
- Contents
- Participants
- Preface
- Black holes, entropy, and information
- Gravitational waves from black-hole mergers
- Out-of-this-world physics: Black holes at future colliders
- Black holes in globular clusters
- Evolution of massive black holes
- Supermassive black holes in deep multiwavelength surveys
- Black-hole masses from reverberation mapping
- Black-hole masses from gas dynamics
- Evolution of supermassive black holes
- Black-hole masses of distant quasars
- The accretion history of supermassive black holes
- Strong field gravity and spin of black holes from broad iron lines
- Birth of massive black-hole binaries
- Dynamics around supermassive black holes
- Black-hole formation and growth: Simulations in general relativity
- Estimating the spins of stellar-mass black holes
- Stellar relaxation processes near the Galactic massive black hole
- Tidal disruptions of stars by supermassive black holes
- Where to look for radiatively inefficient accrection flows in low-luminosity AGN
- Making black holes visible: Accretion, radiation, and jets
Strong field gravity and spin of black holes from broad iron lines
Published online by Cambridge University Press: 11 April 2011
- Frontmatter
- Contents
- Participants
- Preface
- Black holes, entropy, and information
- Gravitational waves from black-hole mergers
- Out-of-this-world physics: Black holes at future colliders
- Black holes in globular clusters
- Evolution of massive black holes
- Supermassive black holes in deep multiwavelength surveys
- Black-hole masses from reverberation mapping
- Black-hole masses from gas dynamics
- Evolution of supermassive black holes
- Black-hole masses of distant quasars
- The accretion history of supermassive black holes
- Strong field gravity and spin of black holes from broad iron lines
- Birth of massive black-hole binaries
- Dynamics around supermassive black holes
- Black-hole formation and growth: Simulations in general relativity
- Estimating the spins of stellar-mass black holes
- Stellar relaxation processes near the Galactic massive black hole
- Tidal disruptions of stars by supermassive black holes
- Where to look for radiatively inefficient accrection flows in low-luminosity AGN
- Making black holes visible: Accretion, radiation, and jets
Summary
Accreting black holes often show iron line emission in their x-ray spectra. When this line emission is very broad or variable, it is likely to originate from close to the black hole. The theory and observations of such broad and variable iron lines are briefly reviewed here. In order for a clear broad line to be found, one or more of the following have to occur: high iron abundance, dense disk surface and minimal complex absorption. Several excellent examples are found from observations of Seyfert galaxies and Galactic Black Holes. In some cases there is strong evidence that the black hole is rapidly spinning. Further examples are expected as more long observations are made with XMM-Newton, Chandra and Suzaku. The x-ray spectra show evidence for the strong gravitational redshifts and light bending expected around black holes.
Introduction
Most of the radiation from luminous accreting black holes is released within the innermost 20 gravitational radii (i.e., 20rg = 20 GM/c2). In such an energetic environment, iron is a major source of x-ray line emission, with strong emission lines in the 6.4–6.9 keV band. Observations of such line emission provides us with a diagnostic of the accretion flow and the behavior of matter and radiation in the strong gravity regime very close to the black hole (Fabian et al. 2000; Reynolds & Nowak 2003; Fabian & Miniutti 2009; Miller 2007).
The rapid x-ray variability found in many Seyfert galaxies is strong evidence for the emission orginating at small radii.
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- Black Holes , pp. 182 - 190Publisher: Cambridge University PressPrint publication year: 2011