Two temperature viscous accretion flows around rotating black holes: Description of under-fed systems to ultra-luminous X-ray sources

Abstract

We discuss two temperature accretion disk flows around rotating black holes. As we know that to explain observed hard X-rays the choice of Keplerian angular momentum profile is not unique, we consider the sub-Keplerian regime of the disk. Without any strict knowledge of the magnetic field structure, we assume the cooling mechanism is dominated by bremsstrahlung process. We show that in a range of Shakura-Sunyaev viscosity parameter $0.2\gsimα\gsim0.0005$, flow behavior varies widely, particularly by means of the size of disk, efficiency of cooling and corresponding temperatures of ions and electrons. We also show that the disk around a rotating black hole is hotter compared to that around a Schwarzschild black hole, rendering a larger difference between ion and electron temperatures in the former case. With all the theoretical solutions in hand, finally we reproduce the observed luminosities ($L$) of two extreme cases -- the under-fed AGNs and quasars (e.g. Sgr $A^{\ast }$) with $L\gsim 10^{33}$ erg/sec to ultra-luminous X-ray sources with $L\sim 10^{41}$ erg/sec, at different combinations of mass accretion rate, ratio of specific heats, Shakura-Sunyaev viscosity parameter and Kerr parameter, and conclude that Sgr $A^{\ast }$ may be an intermediate spinning black hole.

21 pages including 5 figures; few typos corrected; to appear in New Astronomy

References in corpus (10)

• An Unambiguous Detection of Faraday Rotation in Sagittarius A*
• The Nature of SS433 and the Ultraluminous X-ray Sources
• Viscous Torque and Dissipation in the Inner Region of a Thin Accretion Disk: Implications for Measuring Black Hole Spin
• Pseudo-Newtonian gravitational potential for Schwarzschild-de Sitter spacetimes
• Maximum Spin of Black Holes Driving Jets
• Two temperature accretion around rotating black holes: Description of general advective flow paradigm in presence of various cooling processes to explain low to high luminous sources
• Computation of mass loss from viscous accretion disc in presence of cooling
• Limits on the Position Wander of Sgr A*
• Transition from radiatively inefficient to cooling dominated phase in two temperature accretion discs around black holes
• Description of accretion induced outflows from ultra-luminous sources to under-luminous AGNs

Cited by in corpus (5)

• Two temperature accretion around rotating black holes: Description of general advective flow paradigm in presence of various cooling processes to explain low to high luminous sources
• Radiative transfer with POLARIS. II.: Modeling of synthetic Galactic synchrotron observations
• Can the viscosity in astrophysical black hole accretion disks be close to its string theory bound?
• Hydromagnetics of advective accretion flows around black holes: Removal of angular momentum by large scale magnetic stresses
• Variation of the gas and radiation content in the sub-Keplerian accretion disk around black holes and its impact to the solutions