http://arxiv.org/abs/1405.5729
In a recent work we demonstrated that a novel X-ray scaling method, originally introduced for Galactic black holes (GBHs), can be reliably extended to estimate the mass of supermassive black holes accreting at a moderate to high level. Here we investigate the limits of applicability of this method to low-accreting active galactic nuclei, using a control sample with good-quality X-ray data and dynamically measured mass. For low-accreting AGNs, because the basic assumption that the photon index positively correlates with the accretion rate no longer holds the X-ray scaling method cannot be used. Nevertheless, the inverse correlation in the Gamma-Lx/LEdd diagram, found in several low-accreting black holes and confirmed by this sample, can be used to constrain black hole mass within a factor of ~10 from the dynamically determined values. We provide a simple recipe to determine black hole mass using solely X-ray spectral data, which can be used as a sanity check for black hole mass determination based on indirect optical methods.
I. Jang, M. Gliozzi, C. Hughes, et. al.
Fri, 23 May 14
30/44
Comments: 16 pages, 10 figures, 6 tables
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