Black hole accretion discs: reality confronts theory

By Marek Gierlinski, C. Done. 2003

172 citations recorded by the source corpus.

Disc spectra from highly luminous black hole binaries are observed to be rather simple, despite theoretical predictions to the contrary. We collate the disc-dominated spectra from multiple observations of 10 separate sources and show that they are consistent with a simple multicolour blackbody with a disc luminosity of L disc T 4 over two orders of magnitude. This is probably compatible with the predictions of standard Shakura-Sunyaev α-disc theory. However, these models also predict that the radiation-pressure-dominated disc is unstable, in strong conflict to the observed lack of variability of the light curves. We show that this discrepancy is unlikely to be resolved by modifications such as additional energy loss in a jet, a wind or a corona. This motivates consideration of alternative disc models, in particular the β-discs, where the viscous heating is proportional to gas pressure, which are stable. While proper calculations have yet to be performed, it seems likely that such models predict significant departures from a simple L disc T4 relation, again in conflict with the observations. More generally, this shows that accretion disc spectra can give reliable constraints on the disc structure, and should be used to test the next generation of accretion disc models, in which the disc viscosity is calculated self-consistently from the magnetically generated turbulent dynamo.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/87295211678601a4b4c303c8ec7e51707d82f247

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Citations in the corpus

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets (2013, background): “…states of black hole binaries has been demonstrated for many sources by showing that the bolometric luminosity of the thermal component is approximately proportional to T 4in (Kubota et al. 2001; Kubota & Makishima 2004; Gierli´nski & Done 2004; Abe et al. 2005; McClintock et al. 2009).”
Measuring the spins of accreting black holes (2011, background): “…state has been presented for a number of sources via plots showing that the bolometric luminosity of the thermal component is approximately proportional to T 4in (e.g., Kubota et al 2001, Kubota and Makishima 2004, Gierliński and Done 2004, Abe et al 2005, McClintock et al 2009, Dunn et al 2010).”
Modelling the behaviour of accretion flows in X-ray binaries (2007, background): “This is only appropriate for a radiation pressure dominated disc and breaks down at low Ṁ where the disc is gas pressure dominated and has stronger density/temperature gradients (Gierliński & Done 2004).”
General relativistic magnetohydrodynamic simulations of the jet formation and large-scale propagation from black hole accretion systems (2006, background): “Gierliński & Done (2004) suggest that at least some systems, such as GRS 1915+105, have slowly rotating black c© 2006 RAS, MNRAS 000, 1–25 holes (but see Cui et al. 1998).”
Total and Jet Blandford-Znajek Power in the Presence of an Accretion Disk (2005, background): “Black hole X-ray binaries might havea/M ∼ 0.5–0.95 (Gammie et al. 2004), while some may havea/M 0.5 (Gierliński & Done 2004).”
Supercritically accreting stellar mass black holes as ultraluminous X-ray sources (2006, background): “They closely follow the standardL ∝ T 4max dependence (except LMC X-1, see Gierliński & Done 2004, and Fig.”
Extreme gravitational lensing near rotating black holes (2004, background): “…there is clear observational evidence for an inner- most stable orbit in the disc dominanted spectra of galactic black hole binaries (Ebisawa et al. 1993; Kubota et al. 1999; Gierliński & Done 2004), so it seems likely that the accretion flow can take the standard thin disc form assumed here.”
A physical model of the broad-band continuum of AGN and its implications for the UV/X relation and optical variability (2018, background): “These often show spectra at Lbol/LEdd ∼ 0.1–0.2 which are dominated by the thermal accretion disc emission, with only a small tail to higher energies from a hot Comptonisating corona (e.g., Kubota, Makishima, & Ebisawa 2001; Gierliński & Done 2004a; Steiner et al. 2009).”
Testing Accretion Disk Theory in Black Hole X-Ray Binaries (2006, methodology): “Source Selection Our work is motivated in part by spectral fitting of BHBs performed by Gierlinski & Done (2004).”
The Spin of the Near-Extreme Kerr Black Hole GRS 1915+105 (2006, background): “Further strong evidence for a thermal disk interpretation is provided by plots of the observed disk flux versus apparent temperature, which track the expected L ∝ T 4 relation for a constant inner disk radius (Gierlinśki & Done 2004; Kubota & Done 2004).”
Multitemperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations (2004, methodology): “For example, Zhang et al. (1997) and Gierliński & Done (2004) apply correction factors to the temperature and the flux derived from DISKBB.”
Estimating the Spin of Stellar-Mass Black Holes by Spectral Fitting of the X-Ray Continuum (2005, methodology): “This state is consistent with a simple multicolor blackbody model (Gierlinski & Done 2004), making it amenable to theoretical modeling.”
Ultraluminous X-ray sources in the Chandra and XMM-Newton era (2011, methodology): “The other group (including among others NGC 5408 X-1) has similar variability levels and power spectra as luminous Galactic BHBs and AGN in the observed frequency bandpass (10−3–1 Hz).”