Radiative Processes and Geometry of Spectral States of Black-Hole Binaries
arXiv:astro-ph/0001078
Abstract
I review radiative processes responsible for X-ray emission in the hard (low) and soft (high) spectral states of black-hole binaries. The main process in the hard state appears to be thermal Comptonization (in a hot plasma) of blackbody photons emitted by a cold disk. This is supported by correlations between the spectral index, the strength of Compton reflection, and the peak frequencies in the power density spectrum, as well as by the frequency-dependence of Fourier-resolved spectra. Spectral variability may then be driven by the variable truncation radius of the disk. The soft state appears to correspond to the smallest truncation radii. However, the lack of high-energy cutoffs observed in the soft state implies that its main radiative process is Compton scattering of disk photons by non-thermal electrons. The bulk-motion Componization model for the soft state is shown to be ruled out by the data.
arXiv commentInvited review for IAU Symp. 195, Highly Energetic Physical Processes and Mechanisms for Emission from Astrophysical Plasmas, P. C. H. Martens, S. Tsuruta, & M. A. Weber, eds., ASP, pp. 153-170 (2000)
References in corpus (31)
- Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
- Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991
- Thermal Equilibria of Accretion Disks
- Spectral Properties of Accretion Disks Around Galactic and Extragalactic Black Holes
- Radiation mechanisms and geometry of Cygnus X-1 in the soft state
- Plasma Ejection from Magnetic Flares and the X-ray Spectrum of Cygnus X-1
- Correlation between Compton reflection and X-ray slope in Seyferts and X-ray binaries
- Spectral Transitions in Cyg X-1 and Other Black Hole X-Ray Binaries
- Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE
- Spectral evolution of magnetic flares and time lags in accreting black hole sources
- Broad-band X-ray/gamma-ray spectra and binary parameters of GX 339-4 and their astrophysical implications
- Gamma-Ray Spectral States of Galactic Black Hole Candidates
- X-ray Spectral Formation in a Converging Fluid Flow: Spherical Accretion into Black Holes
- Temporal Properties of Cygnus X-1 During the Spectral Transitions
- Simultaneous EUVE/ASCA/RXTE Observations of NGC 5548
- The converging inflow spectrum is an intrinsic signature for a black hole: Monte-Carlo simulations of Comptonization on free-falling electrons
- X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies
- X-ray spectral evolution of GS 2023+338 (V404 Cyg) during decline after outburst
- Evolution of the accretion flow in Nova Muscae 1991
- Relativistic Distortions in the X-ray Spectrum of Cyg X-1
- On the Spectral Slopes of Hard X-ray Emission from Black Hole Candidates
- A New Model for the Hard Time Lags in Black Hole X-Ray Binaries
- Do the Spectra of Soft X-ray Transients Reveal Bulk Motion Inflow Phenomenon?
- Hot accretion discs with thermal Comptonisation and advection in luminous black hole sources
- Broad-band X-Ray Spectra of the Black Hole Candidate GRO J1655-40
- Mass Determination of Black Holes in LMC X-1 and Nova Muscae 1991 from their High-Energy Spectra
- The High-Energy Spectra of Accreting Black Holes: Observational Evidence for Bulk-Motion Infall
- Simultaneous ASCA And RXTE Observations of Cygnus X--1 During Its 1996 State Transition
- Detecting Compton Reflection and a Broad Iron Line in MCG-5-23-16 with the Rossi X-ray Timing Explorer
- Temporal and Spectral Correlations of Cyg X-1
- An RXTE Observation of the Seyfert 1 Galaxy MCG-6-30-15 : X-ray Reflection and the Iron Abundance