Black hole accretion discs in the canonical low‐hard state
By R. Reis, A. C. Fabian, Jon M. Miller. 2009
140 citations recorded by the source corpus.
Stellar mass black holes in the low-hard state may hold clues to jet formation and basic accretion disc physics, but the nature of the accretion flow remains uncertain. A standard thin disc can extend close to the innermost stable circular orbit, but the inner disc may evaporate when the mass accretion rate is reduced. Blackbody-like continuum emission and dynamically broadened iron emission lines provide independent means of probing the radial extent of the inner disc. Here, we present an X-ray study of eight black holes in the low-hard state. A thermal-disc continuum with a colour temperature consistent with L ∝ T 4 is clearly detected in all eight sources, down to ≈5 x 10 ―4 L Edd . In six sources, disc models exclude a truncation radius larger than 10r g . Iron Kα fluorescence line emission is observed in half of the sample, down to luminosities of ≈1.5 x 10 ―3 L Edd . Detailed fits to the line profiles exclude a truncated disc in each case. If strong evidence of truncation is defined as (1) a non-detection of a broad iron line and (2) an inner disc temperature much cooler than expected from the L ∝ T 4 relation, none of the spectra in this sample offers strong evidence of disc truncation. This suggests that the inner disc may evaporate at or below ≈1.5 x 10 ―3 L Edd .
Subfields: Astronomy and Astrophysics, Biomedical Engineering
View Paper: https://www.semanticscholar.org/paper/2239f834c1b85db05554d3d01843eab5f168d212
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In Astronomy and Astrophysics
- Ramesh Narayan
- F. Yuan
- M. Miller
- Jonathan M. Miller
- T. Johannsen
- Cosimo Bambi
- A. Sa̧dowski
- J. McKinney
In Biomedical Engineering
Citations in the corpus
- The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes (2014, background): “[188, 189], [190], [191]); an older, more conservative, and theorybased guideline might be L/LEdd ≥ 10 ([192]).”
- Hot Accretion Flows Around Black Holes (2014, methodology): “These observations have been used to argue that the thin disk is not truncated but extends down to the ISCO (e.g., Miller et al. 2006, Rykoff et al. 2007, Ramadevi & Seetha 2007, Reis et al. 2010).”