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The Effects of High Density on the X-ray Spectrum Reflected from Accretion Discs Around Black HolesCurrent models of the spectrum of X-rays reflected from accretion discs around black holes and other compact objects are commonly calculated assuming that the density of the disc atmosphere is constant within several Thomson depths from the irradiated surface. An important simplifying assumption of these models is that the ionization structure of the gas is completely specified by a single, fixed value of the ionization parameter (xi), which is the ratio of the incident flux to the gas density. The density is typically fixed at n(sub e) = 10(exp 15) per cu cm. Motivated by observations, we consider higher densities in the calculation of the reflected spectrum. We show by computing model spectra for n(sub e) approximately greater than 10(exp 17) per cu cm that high-density effects significantly modify reflection spectra. The main effect is to boost the thermal continuum at energies 2 approximately less than keV. We discuss the implications of these results for interpreting observations of both active galactic nuclei and black hole binaries. We also discuss the limitations of our models imposed by the quality of the atomic data currently available.
Document ID
20170003433
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Garcia, Javier A. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Fabian, Andrew C. (Institute of Astronomy Cambridge, United Kingdom)
Kallman, Timothy R. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Dauser, Thomas (Erlangen-Nuernberg Univ. Bamberg, Germany)
Parker, Micahel L. (Institute of Astronomy Cambridge, United Kingdom)
McClintock, Jeffrey E. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Steiner, James F. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Wilms, Jorn (Erlangen-Nuernberg Univ. Bamberg, Germany)
Date Acquired
April 14, 2017
Publication Date
July 14, 2016
Publication Information
Publication: Monthly Notices of the Royal Astromical Society
Volume: 462
Issue: 1
ISSN: 0035-8711
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN41170
Funding Number(s)
CONTRACT_GRANT: PF5-160144
CONTRACT_GRANT: ERC 340442
Distribution Limits
Public
Copyright
Other
Keywords
accretion
process-line: formation - radiative
accretion
disc-atomic