Variability of black hole accretion discs: The cool, thermal disc component

Abstract

We extend the model of King et al. (2004) for variability in black hole accretion discs, by taking proper account of the thermal properties of the disc. Because the degree of variability in the King et al. (2004) model depends sensitively on the ratio of disc thickness to radius, H/R, it is important to follow the time-dependence of the local disc structure as the variability proceeds. In common with previous authors, we develop a one-zone model for the local disc structure. We agree that radial heat advection plays an important role in determining the inner disc structure, and also find limit-cycle behaviour. When the stochastic magnetic dynamo model of King et al. (2004) is added to these models, we find similar variability behaviour to before. We are now better placed to put physical constraints on model parameters. In particular, we find that in order to be consistent with the low degree of variability seen in the thermal disc component of black hole binaries, we need to limit the energy density of the poloidal field that can be produced by local dynamo cells in the disc to less than a few percent of the energy density of the dynamo field within the disc itself.

18 pages, 17 figures, accepted by MNRAS

References in corpus (24)

• On characterising the variability properties of X-ray light curves from active galaxies
• The disc instability model of dwarf-novae and low-mass X-ray binary transients
• RXTE Observation of Cygnus X-1: II. Timing Analysis
• Non-linear X-ray variability in X-ray binaries and active galaxies
• Measuring the broadband power spectra of active galactic nuclei with RXTE
• The flux-dependent amplitude of broadband noise variability in X-ray binaries and active galaxies
• Soft state of Cygnus X-1: stable disk and unstable corona
• X-ray Fluctuation Power Spectral Densities of Seyfert 1 Galaxies
• The Three Spectral Regimes Found in the Stellar Black Hole XTE J1550--564 in its High/Soft State
• Variability in black hole accretion discs
• Radiation pressure instability driven variability in the accreting black holes
• Spectral and Timing Evolution of the Black Hole X-ray Nova 4U 1543-47 During its 2002 Outburst
• Time-Dependent Disk Models for the Microquasar GRS1915+105
• The Disk-Jet Connection in Microquasars and AGN
• Limit-Cycle Behaviour of Thermally-Unstable Accretion Flows onto Black Holes
• Advective Accretion Disks and Related Problems Including Magnetic Fields
• GRS 1915+105: the distance, radiative processes and energy-dependent variability
• A Good Long Look at the Black Hole Candidates LMC X-1 and LMC X-3
• Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630-47
• A close look at the state transitions of Galactic black hole transients during outburst decay
• SAX J1808.4-3658 and the origin of X-ray variability in X-ray binaries and active galactic nuclei
• On the thermal stability of transonic accretion discs
• Stationary Population III accretion discs
• Non-linear evolution of thermally unstable slim accretion discs with a diffusive form of viscosity

Cited by in corpus (26)

• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• Radio-Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications
• A Stochastic Model for the Luminosity Fluctuations of Accreting Black Holes
• On different types of instabilities in black hole accretion discs. Implications for X-ray binaries and AGN
• The origin of variability of the intermediate-mass black-hole ULX system HLX-1 in ESO 243-49
• Power spectra of black holes and neutron stars as a probe of hydrodynamical structure of the source. Diffusion theory and its application to Cyg X-1 and Cyg X-2 X-ray observations
• Extracting Information from AGN Variability
• Modified models of radiation pressure instability in application to 10, 10${}^5$, and 10${}^7$ $M_{\odot }$ accreting black holes
• Time-dependent models of two-phase accretion discs around black holes
• The thermal-viscous disk instability model in the AGN context
• The nature of the intranight variability of radio-quiet quasars
• The influence of accretion disk thickness on the large-scale magnetic dynamo
• Studies of Thermally Unstable Accretion Disks around Black Holes with Adaptive Pseudo-Spectral Domain Decomposition Method I. Limit-Cycle Behavior in the Case of Moderate Viscosity
• Internal shocks driven by accretion flow variability in the compact jet of the black hole binary GX 339-4
• Unraveling the foretime of GRS 1915+105 using AstroSat observations: Wide-band spectral and temporal characteristics
• Stabilization of radiation pressure dominated accretion disks by viscous fluctuations
• Accretion geometry of the black hole binary MAXI J1820+070 probed by frequency-resolved spectroscopy
• The Dynamics and Energetics of Remnant and Restarting RLAGN
• Accreting corona model of the X-ray variability in soft state X-ray binaries and active galactic nuclei
• Variabilities of Gamma-ray Bursts from Black Hole Hyper-accretion Disks
• Studies of Thermally Unstable Accretion Disks around Black Holes with Adaptive Pseudospectral Domain Decomposition Method. II. Limit-Cycle Behavior in accretion disks around Kerr black holes
• Damped harmonic oscillator interpretation of the soft-state power spectra of Cyg X-1
• Radio-loudness of Active Galaxies and the Black Hole Evolution
• The influence of outflows on the 1/f-like luminosity fluctuations
• Correlations of Disk and Jet Emission Deviating from the Fundamental Plane
• Dirty waveforms: multiband harmonic content of gas-embedded gravitational wave sources