Low angular momentum flow model II for Sgr A*

Abstract

We examine 1D two-temperature accretion flows around a supermassive black hole, adopting the specific angular momentum λ, the total specific energy εand the input accretion rate \dot M_{input} = 4.0x10^{-6} solar mass/yr estimated in the recent analysis of stellar wind of nearby stars around Sgr A*. The two-temperature flow is almost adiabatic even if we take account of the heating of electrons by ions, the bremsstrahlung cooling and the synchrotron cooling, as long as the ratio βof the magnetic energy density to the thermal energy density is taken to be as β< 1. The different temperatures of ions and electrons are caused by the different adiabatic indices of ions and electrons which depend on their temperature states under the relativistic regime. The total luminosity increases with increasing βand results in - 10^{35} - 10^{36} erg/s for β=10^{-3} - 1. Furthermore, from 2D time-dependent hydrodynamical calculations of the above flow, we find that the irregularly oscillating shocks are formed in the inner region and that the luminosity and the mass-outflow rate vary by a factor of 2 -- 3 and 1.5 -- 4, respectively. The time variability may be relevant to the flare activity of Sgr A*.

8 pages, 6 figures. arXiv admin note: text overlap with arXiv:1206.5338

References in corpus (5)

• Advection-Dominated Accretion and the Black Hole Event Horizon
• Polarimetry of near-infrared flares from Sagittarius A*
• A polarised infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots
• Near-infrared polarimetry setting constraints on the orbiting spot model for Sgr A* flares
• K-band polarimetry of an Sgr A* flare with a clear sub-flare structure

Cited by in corpus (3)

• Estimation of mass outflow rates from dissipative accretion disc around rotating black holes
• A Possible Model for the Long-Term Flares of Sgr A*
• Accretion-ejection in rotating black holes: a model for `outliers' track of radio-X-ray correlation in X-ray binaries