Multitemperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations

By Li-Xin Li, E. Zimmerman, Ramesh Narayan, J. E. McClintock. 2004

338 citations recorded by the source corpus.

We use a ray-tracing technique to compute the observed spectrum of a thin accretion disk around a Kerr black hole. We include all relativistic effects such as frame-dragging, Doppler boost, gravitational redshift, and bending of light by the gravity of the black hole. We also include self-irradiation of the disk as a result of light deflection. Assuming that the disk emission is locally blackbody, we show how the observed spectrum depends on the spin of the black hole, the inclination of the disk, and the torque at the inner edge of the disk. We find that the effect of a nonzero torque on the spectrum can, to a good approximation, be absorbed into a zero-torque model by adjusting the mass accretion rate and the normalization. We describe a computer model, called KERRBB, which we have developed for fitting the spectra of black hole X-ray binaries. Using KERRBB within the X-ray data reduction package XSPEC, and assuming a spectral hardening factor fcol = 1.7, we analyze the spectra of three black hole X-ray binaries: 4U 1543-47, XTE J1550-564, and GRO J1655-40. We estimate the spin parameters of the black holes in 4U 1543-47 and GRO J1655-40 to be a/M ∼ 0.6 and ∼0.6-0.7, respectively. If fcol ∼ 1.5-1.6, as in a recent study, then we find a/M ∼ 0.7-0.8 and ∼0.8-0.9, respectively. These estimates are subject to additional uncertainties in the assumed black hole masses, distances, and disk inclinations.

Subfields: Astronomy and Astrophysics, Biomedical Engineering

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Citations in the corpus

Testing Accretion Disk Theory in Black Hole X-Ray Binaries (2006, methodology): “One of the most sophisticated models of this type is the KERRBB model (Li et al. 2005) for Xspec (Arnaud 1996).”
THE CONSTANT INNER-DISK RADIUS OF LMC X-3: A BASIS FOR MEASURING BLACK HOLE SPIN (2010, positive): “The thermal and principal component of our model is kerrbb2, a thin accretion disk model that includes all relativistic effects, self-irradiation of the disk (“returning radiation”), limb darkening, and the effects of spectral hardening (Li et al. 2005; McClintock et al. 2006).”
Measuring the spins of accreting black holes (2011, methodology): “KERRBB assumes the NT model of the disk and carries out all the necessary ray-tracing to relate disk properties to observables.”
A PARALLAX DISTANCE TO THE MICROQUASAR GRS 1915+105 AND A REVISED ESTIMATE OF ITS BLACK HOLE MASS (2014, methodology): “We modeled the spectra using the relativistic disk model kerrbb2 (McClintock et al. 2006; Li et al. 2005; Davis & Hubeny 2006) and a cutoff Compton power-law component simplcut, a variant of simpl (Steiner et al. 2009b).”
Simulations of magnetized discs around black holes: Effects of black hole spin, disc thickness and magnetic field geometry (2010, background): “Whether or not the total luminosity of the disc agrees with the NT model is not important since, in spectral modelling of data, one invariably fits a normalization (e.g. the accretion rate Ṁ in the model KERRBB; Li et al. 2005) which absorbs any deviations in this quantity.”
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).”
A systematic look at the Very High and Low/Hard state of GX 339-4: Constraining the black hole spin with a new reflection model (2008, methodology): “…check on any inconsistency that may arise from using a single temperature disc reflection model to constrain the spin of the black hole, we investigated the VHS with a different thermal model, (KERRBB, Li et al. 2005), whic includes relativistic smearing in a disc with radial temperatu e gradient.”
THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 (2011, methodology): “Herein, we use these results to determine the spin of the black hole primary by fitting the thermal component of its X-ray spectrum to our implementation of the Novikov-Thorne model7 of a thin accretion disk (Li et al. 2005).”
Testing black hole candidates with electromagnetic radiation (2015, methodology): “The continuum-fitting method consists of the analysis of the thermal spectrum of geometrically thin and optically thick accretion disks (Li et al., 2005; McClintock et al., 2014; Zhang et al., 1997).”
THE SIZES OF THE X-RAY AND OPTICAL EMISSION REGIONS OF RXJ 1131–1231 (2009, background): “Many of these effects are included in recent disk models such as Hubeny et al. (2001) or Li et al. (2005) for disk spectra.”
X-Ray Properties of Black-Hole Binaries (2006, methodology): “Fortunately, accretion disk models for Kerr BHs have recently become publicly available (Li et al. 2005; Dovčiak et al. 2005), and there now exists a fully-relativistic treatment of the effects of spectral hardening (Davis et al. 2005) .”
The Ultraluminous State (2009, background): “Firstly, relativistic effects broaden the spectrum, so it is less strongly peaked than an MCD (Cunningham 1975; Ebisawa et al. 2001; Li et al. 2005).”
THE TRIGONOMETRIC PARALLAX OF CYGNUS X-1 (2011, background): “Rin can be determined by fitting the X-ray continuum emission from the BH’s accretion disk to a fully relativistic model if the BH mass, distance, and accretion disk inclination angle are known (Li et al. 2005).”
Estimating the Spin of Stellar-Mass Black Holes by Spectral Fitting of the X-Ray Continuum (2005, methodology): “1, Postfach 1317, 85741 Garching, Ger- many 5Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 black hole (Li et al. 2005).”
The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes (2014, background): “ending on the nature of the corona (e.g. [288]). New models for accretion disks capture all of these parameters and are able to turn these absolute photon ﬂux measurements into black hole spins (e.g. [289], [209]). Figure 4 depicts the inﬂuence of spin on the accretion disk continuum. Distances with”