Relativistic Accretion Disk Models of High-State Black Hole X-Ray Binary Spectra

By S. Davis, O. Blaes, I. Hubeny, N. J. Turner. 2004

219 citations recorded by the source corpus.

We present calculations of non-LTE, relativistic accretion disk models applicable to the high/soft state of black hole X-ray binaries. We include the effects of thermal Comptonization and bound-free and free-free opacities of all abundant ion species. Taking into account the relativistic propagation of photons from the local disk surface to an observer at infinity, we present spectra calculated for a variety of accretion rates, black hole spin parameters, disk inclinations, and stress prescriptions. We also consider nonzero inner torques on the disk and explore different vertical dissipation profiles, including some that are motivated by recent radiation magnetohydrodynamic (MHD) simulations of magnetorotational turbulence. Bound-free metal opacity generally produces significantly less spectral hardening than previous models that only considered Compton scattering and free-free opacity. We find that the resulting effective photosphere usually lies at a small fraction of the total column depth, producing spectra that are remarkably independent of the stress prescription and vertical structure assumptions. We provide detailed comparisons between our models and the widely used multicolor disk model. Frequency-dependent discrepancies exist that may affect the parameters of other spectral components when this simpler disk model is used to fit modern X-ray data. For a given source, our models predict that the luminosity in the high/soft state should approximately scale with the fourth power of the empirically inferred maximum temperature, but with a slight hardening at high luminosities. This is in good agreement with observations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/18dd1138503a3ea265b68ad5a6a09e2bf6104858

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

X-Ray Properties of Black-Hole Binaries (2006, methodology): “…2005; “KY”, Dovčiak et al. 2004) that include all relativistic effects and allow one to fit for a∗; and (2) sophisticated disk atmosphere models now exist for computing the spectral hardening factor, fcol = Tcol/Teff as a function of the Eddington-scaled luminosity of the disk (Davis et al. 2005).”
Estimating the Spin of Stellar-Mass Black Holes by Spectral Fitting of the X-Ray Continuum (2005, background): “…of the disk, the effects of limb darkening, and a spectral hardening factor fcol to relate the color temperature Tcol and the effective temperature Teff of the disk emission: fcol = Tcol/Teff (Shimura & Takahara 1995, hereafter ST95; Merloni, Fabian & Ross 2000; Davis et al. 2005, hereafter D05).”
Measuring the spins of accreting black holes (2011, methodology): “To carry out this correction we use the advanced disk atmosphere models of Davis et al (2005) and Davis and Hubeny (2006).”
Intrinsic disc emission and the soft X‐ray excess in active galactic nuclei (2011, background): “Comptonisation of the disc emission could occur in the disc itself if there is enhanced dissipation in the upper layers of the disc, over and above that expected from the ShakuraSunyaev prescription (e.g. Davis et al 2005).”
Modelling the behaviour of accretion flows in X-ray binaries (2007, background): “These new models also directly incorporate the stress free inner boundary condition, and self–consistently propagate the escaping radiation through the curved spacetime (Davis et al. 2005; Davis & Hubeny 2006).”
Radiation Pressure-supported Starburst Disks and Active Galactic Nucleus Fueling (2005, background): “An equation f r the vertical generation of energy,dF/dz, is also needed (e.g., Davis et al. 2005).”
The spin of the black hole microquasar XTE J1550−564 via the continuum-fitting and Fe-line methods (2010, methodology): “In practice, we fit the X-ray spectrum of the BH’s accretion disc to our version of the Novikov–Thorne thin accretion disc model (Novikov & Thorne 1973; Li et al. 2005; McClintock et al. 2006) using an advanced treatment of spectral hardening (Davis et al. 2005; Davis & Hubeny 2006).”
Testing Accretion Disk Theory in Black Hole X-Ray Binaries (2006, methodology): “Alternatively, this behavior is qualitatively consistent with the increased spectral hardening with accretion rate in the local disk atmospheres, ignoring advection (Davis et al. 2005; Shafee et al. 2006).”
Testing black hole candidates with electromagnetic radiation (2015, background): “Corrections for non-blackbody effects are usually taken into account by introducing the color factor, which is obtained from disk atmosphere models and there is not a unani- 20 mous consensus on their reliability (Davis et al., 2005; Davis & Hubeny, 2006).”
A physical model of the broad-band continuum of AGN and its implications for the UV/X relation and optical variability (2018, background): “14 of Davis et al. 2005).”
The Spin of the Near-Extreme Kerr Black Hole GRS 1915+105 (2006, methodology): “Recently, we have firmly established the methodology pioneered by Zhang et al. and Gierlinśki et al. by constructing relativistic accretion disk models (Li et al. 2005; Davis et al. 2005) and by modeling in detail the effects of spectral hardening (Davis et al. 2005, 2006).”
The Ultraluminous State (2009, background): “Secondly, the intrinsic spectrum frommaterial at a given radius is not a true blackbody as there is not enugh absorption opacity to thermalise the emission at all energies (Davis et al 2005).”
Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets (2013, methodology): “In practice, one usually ﬁts the thermal component using kerrbb2 (McClintock et al. 2006) 3 , which is a hybrid code implemented in XSPEC (Arnaud 1996) that combines the capabilities of two relativistic disk models, bhspec (Davis et al. 2005) and kerrbb (Li et al. 2005).”
Black hole accretion discs in the canonical low‐hard state (2009, background): “Davis et al. (2005) showed that below a colour temperature of ∼1 keV the colour correction factor is indeed a constant close to 1.7.”
THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 (2011, methodology): “The entries in the look-up tables forf were computed using bothKERRBB and a second relativistic disk modelBHSPEC (Davis et al. 2005; Davis & Hubeny 2006).”
Global General Relativistic Magnetohydrodynamic Simulation of a Tilted Black Hole Accretion Disk (2007, background): “On the other hand, for flows that are effectively optically thick Davis et al. (2005) found that the emergent spectra are remarkably independent of the overall stress and surface density.”