X-ray Probes of Black Hole Accretion Disks for Testing the No-Hair Theorem
arXiv:1501.02815 · doi:10.1103/PhysRevD.90.064002
Abstract
The spins of a number of supermassive and stellar-mass black holes have been measured based on detections of thermal continuum emission and relativistically broadened iron lines in their x-ray spectra. Likewise, quasiperiodic variability has been observed in several sources. Such measurements commonly make the assumption that black holes are described by the Kerr metric, which according to the no-hair theorem characterizes black holes uniquely in terms of their masses and spins. This fundamental property of black holes can be tested observationally by measuring potential deviations from the Kerr metric introduced by a parametrically deformed Kerr-like spacetime. Thermal spectra, iron lines, and variability have already been studied extensively in several such metrics, which usually depend on only one particular type of deviation or contain unphysical regions outside of the compact object. In this paper, I study these x-ray probes in the background of a new Kerr-like metric which depends on four independent deviation functions and is free of pathological regions outside of the event horizon. I show that the observed signals depend significantly on primarily two types of deviations and that the strong correlation between the spin and the deviation parameters found previously in other Kerr-like metrics is partially broken for rapidly spinning black holes. This suggests that high-spin sources are the best candidates for tests of the no-hair theorem with x-rays and I obtain first constraints on such deviations from the stellar-mass black hole Cygnus X-1.
18 pages, 13 figures
References in corpus (17)
- Constraining Black Hole Spin Via X-ray Spectroscopy
- A Metric for Rapidly Spinning Black Holes Suitable for Strong-Field Tests of the No-Hair Theorem
- Dynamical Chern-Simons Modified Gravity I: Spinning Black Holes in the Slow-Rotation Approximation
- Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-Dilaton-Gauss-Bonnet black holes
- Testing the general relativistic ''no-hair'' theorems using the galactic center black hole SgrA*
- Non-Spinning Black Holes in Alternative Theories of Gravity
- Photon Rings around Kerr and Kerr-like Black Holes
- Broad iron K-alpha emission lines as a diagnostic of black hole spin
- Testing Accretion Disk Theory in Black Hole X-ray Binaries
- Bumpy Black Holes in Alternate Theories of Gravity
- A code to compute the emission of thin accretion disks in non-Kerr space-times and test the nature of black hole candidates
- Shape and position of the shadow in the Tomimatsu-Sato space-time
- Testing the space-time geometry around black hole candidates with the analysis of the broad K iron line
- Probing the space-time geometry around black hole candidates with the resonance models for high-frequency QPOs and comparison with the continuum-fitting method
- A 200-s Quasi-Periodicity Following the Tidal Disruption of a Star by a Dormant Black Hole
- (Sort of) Testing relativity with extreme mass ratio inspirals
- Extremal energy shifts of radiation from a ring near a rotating black hole