Modelling the behaviour of accretion flows in X-ray binaries

By C. Done, Marek Gierlinski, Aya Kubota. 2007

974 citations recorded by the source corpus.

We review how the recent increase in X-ray and radio data from black hole and neutron star binaries can be merged together with theoretical advances to give a coherent picture of the physics of the accretion flow in strong gravity. Both long term X-ray light curves, X-ray spectra, the rapid X-ray variability and the radio jet behaviour are consistent with a model where a standard outer accretion disc is truncated at low luminosities, being replaced by a hot, inner flow which also acts as the launching site of the jet. Decreasing the disc truncation radius leads to softer spectra, as well as higher frequencies (including quasi periodic oscillations, QPOs) in the power spectra, and a faster jet. The collapse of the hot flow when the disc reaches the last stable orbit triggers the dramatic decrease in radio flux, as well as giving a qualitative (and often quantitative) explanation for the major hard–soft spectral transition seen in black holes. The neutron stars are also consistent with the same models, but with an additional component due to their surface, giving implicit evidence for the event horizon in black holes. We review claims of observational data which conflict with this picture, but show that these can also be consistent with the truncated disc model. We also review suggested alternative models for the accretion flow which do not involve a truncated disc. The most successful of these converge on a similar geometry, where there is a transition at some radius larger than the last stable orbit between a standard disc and an inner, jet dominated region, with the X-ray source associated with a mildly relativistic outflow, beamed away from the disc. However, the observed uniformity of properties between black holes at different inclinations suggests that even weak beaming of the X-ray emission may be constrained by the data. After collapse of the hot inner flow, the spectrum in black hole systems can be dominated by the disc emission. Its behaviour is consistent with the existence of a last stable orbit, and such data can be used to estimate the black hole spin. By contrast, these systems can also show very different spectra at these high luminosities, in which the disc spectrum (and probably structure) is strongly distorted by Comptonization. The structure of the accretion flow becomes increasingly uncertain as the luminosity approaches (and exceeds) the Eddington luminosity, though there is growing evidence that winds may play an important role. We stress that these high Eddington fraction flows are key to understanding many disparate and currently very active fields such as ULX, Narrow Line Seyfert 1’s, and the growth of the first black holes in the Early Universe.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/980148fe3fb547eba6ab2b865bb29746969df935

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Citations in the corpus

Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes (2012, background): “…rates, 10−2 L/LEdd 0.3, efficient cooling sets in, and the inner accretion disc collapses into an optically thick geometrically thin accretion disc (Narayan & Yi 1995; Esin, McClintock & Narayan 1997; Esin et al. 1998; Meyer-Hofmeister & Meyer 2003; McClintock & Remillard 2006; Done et al. 2007).”
Active galactic nuclei: what’s in a name? (2017, background): “2.1.4, Done et al. (2007), and Yuan and Narayan (2014) for more details. this is generally depicted as an atmosphere above the inner accretion disk, though its exact geometry is unknown).”
What drives the growth of black holes (2011, background): “…in response to changes to the BH 3The X-ray variability of AGN seen on intra-day timescales is related to the mass accretion but is unrelated to the accretion-disc state (e.g., Ulrich et al., 1997; Vaughan et al., 2003; Uttley et al., 2005). accretion rate (e.g., Nowak, 1995; Done et al., 2007).”
Low-frequency oscillations in black holes: a spectral-timing approach to the case of GX 339-4 (2011, methodology): “The geometry described in Esin et al. (1997) and Done et al. (2007) allow to explain the spectral evolution seen in BHBs and forms the basis for the LFQPO model proposed by Ingram et al. (2009), Ingram & Done (2010) and Ingram & Done (2011), which invokes Lense-Thirring precession.”
Rapid optical and X-ray timing observations of GX 339-4: multi-component optical variability in the low/hard state (2010, background): “Done et al. 2007) as long as the flow is large enough to encompass the broad range of timescales required by the rms–flux relation.”
Accretion disc variability in the hard state of black hole X-ray binaries (2009, background): “However, see Gierliński et al. 2008; Hiemstra et al. 2009; Done et al. 2007 for arguments in favour of disc truncation at larger radii.”
Hot Accretion Flows Around Black Holes (2014, background): “…the soft-to-hard transition in most sources happens at roughly the same luminosity ∼ 1.5%LEdd, with increasing luminosity the hard-to-soft transition can occur at any of a wide range of luminosities extending up to L ∼ 30%LEdd (Zdziarski & Gierliński 2004, Done et al. 2007, Yu & Yan 2009).”
Active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ∼105 yr (2015, background): “…is injected into the system changes: during the high-Eddington peak, the AGN will produce predominantly radiative energy, while during the low-Eddington troughs, the change in accretion mode means that most of the energy is injected in kinetic form (Done et al. 2007; Alexander & Hickox 2012).”
Measuring the spins of accreting black holes (2011, background): “For supermassive black holes in active galactic nuclei (AGN), this power-law component is dominant, and it is thought to be produced by inverse Compton scattering of soft thermal photons in a hot (kT ∼ 100 keV) corona (Reynolds and Nowak 2003, Done et al 2007).”
Multi-resonance orbital model of high-frequency quasi-periodic oscillations: possible high-precision determination of black hole and neutron star spin (2013, methodology): “…model have to be compared with the spin estimates based on the accretion disc spectral continuum fitting (McClintock et al. 2011; Done & Davis 2008; Done et al. 2007; McClintock et al. 2006; Middleton et al. 2006; Shafee et al. 2006) and profiled spectral lines (Laor 1991; Bao & Stuchlík 1992;…”
Three-dimensional simulations of supercritical black hole accretion discs - luminosities, photon trapping and variability (2015, background): “Radiation coming from accretion disks is known to be highly variable (e.g., Done et al. 2007).”