X-RAY SPECTRA FROM MAGNETOHYDRODYNAMIC SIMULATIONS OF ACCRETING BLACK HOLES

Journal Article · Sat Jun 01 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/769/2/156· OSTI ID:22127208

Schnittman, Jeremy D. ^[1]; Krolik, Julian H. ^[2]

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1. NASA Goddard Space Flight Center Greenbelt, MD 20771 (United States)
2. Department of Physics and Astronomy, Johns Hopkins University Baltimore, MD 21218 (United States)

We present the results of a new global radiation transport code coupled to a general relativistic magnetohydrodynamic simulation of an accreting, non-rotating black hole. For the first time, we are able to explain from first principles in a self-consistent way all the components seen in the X-ray spectra of stellar-mass black holes, including a thermal peak and all the features associated with strong hard X-ray emission: a power law extending to high energies, a Compton reflection hump, and a broad iron line. Varying only the mass accretion rate, we are able to reproduce a wide range of X-ray states seen in most galactic black hole sources. The temperature in the corona is T{sub e} {approx} 10 keV in a boundary layer near the disk and rises smoothly to T{sub e} {approx}> 100 keV in low-density regions far above the disk. Even as the disk's reflection edge varies from the horizon out to Almost-Equal-To 6M as the accretion rate decreases, we find that the shape of the Fe K{alpha} line is remarkably constant. This is because photons emitted from the plunging region are strongly beamed into the horizon and never reach the observer. We have also carried out a basic timing analysis of the spectra and find that the fractional variability increases with photon energy and viewer inclination angle, consistent with the coronal hot spot model for X-ray fluctuations.

• OSTI ID: 22127208
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 769; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
BEAMS
BLACK HOLES
BOUNDARY LAYERS
DENSITY
EMISSION
FLUCTUATIONS
HARD X RADIATION
INCLINATION
IRON
KEV RANGE
MASS
PHOTONS
RADIATION TRANSPORT
REFLECTION
RELATIVISTIC RANGE
SIMULATION
X-RAY SPECTRA