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Computations of Photon Orbits Emitted by Flares at the ISCO of Accretion Disks Around Rotating Black HolesWe present detailed computations of photon orbits emitted by flares at the ISCO of accretion disks around rotating black holes. We show that for sufficiently large spin parameter, i.e. $a > 0.94 M$, following a flare at ISCO, a sufficient number of photons arrive at an observer after multiple orbits around the black hole, to produce an "photon echo" of constant lag, i.e. independent of the relative phase between the black hole and the observer, of $\Delta T \simeq 14 M$. This constant time delay, then, leads to the presence of a QPO in the source power spectrum at a frequency $\nu \simeq 1/14M \simeq 10 (M_[\odot]/M])$ kHz, even for a totally random ensemble of such flares. Observation of such a QPO will provide incontrovertible evidence for the high spin of the black hole and a very accurate, independent, measurement of its mass.
Document ID
20090032314
Acquisition Source
Goddard Space Flight Center
Document Type
Presentation
Authors
Kazanas, Demosthenes
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Fukumura, K.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
September 7, 2009
Subject Category
Astrophysics
Meeting Information
Meeting: X-Ray Astronomy 2009: Present Status, Multi-Wavelength Approach and Future Perspectives
Location: Bologna
Country: Italy
Start Date: September 7, 2009
End Date: September 11, 2009
Sponsors: Instituto Nazionale Di Astrofisica
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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