A Swift Survey of Accretion onto Stellar-Mass Black Holes
Abstract
We present a systemic analysis of all of the stellar mass black hole binaries (confirmed \& candidate) observed by the Swift observatory up to June 2010. The broad Swift bandpass enables a trace of disk evolution over an unprecedented range in flux and temperature. The observed spectra have an average luminosity of $\sim$ 1\% Eddington, though we are sensitive to accretion disks down to a luminosity of 10^{-3 L_Edd. We will present the primary results of this survey: (i) There is no evidence for large scale truncation of the accretion disk in the hard state (at least for L_x \gtrsim 10^{-3 L_Edd), with all of the accretion disks having radii \lesssim 4 R_g. (ii) The broadband spectra (X-ray -- Opt/UV) reveal irradiation of the accretion disk to be an important effect at all luminosities sampled herein, i.e, L_x \gtrsim 10^{-3 L_Edd$. (iii) The Swift data reveal a relation between the flux emitted by the accretion disk and that emitted by the corona that is found to be in broad agreement with the observed disk -- corona relationship in Seyfert galaxies, suggesting a scale invariant coupling between the accretion disk and the corona.
- Publication:
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AAS/High Energy Astrophysics Division #13
- Pub Date:
- April 2013
- Bibcode:
- 2013HEAD...1312623R