Probing the two temperature paradigm for advection dominated accretion flow: test for the component thermalization time-scale passed

Abstract

We report here on a calculation of thermalization time-scale of the two temperature advection dominated accretion flow (ADAF) model. It is established that time required to equalize the electron and ion temperatures via electron-ion collisions in the ADAF with plausible physical parameters greatly exceeds age of the Universe, which corroborates validity one of the crucial assumptions of the ADAF model, namely the existence of a hot two temperature plasma. This work is motivated by the recent success (Mahadevan 1998a,b) of ADAF model in explaining the emitted spectrum of Sgr A*.