Mass accretion rate of the galactic black hole A0620-00 in its quiescent state

Abstract

Our recent radio observation using the Giant Meter Radio Telescope (GMRT) of the galactic black hole transient A0620-00 at 1.280GHz revealed a micro-flare of a few milli-Jansky. Assuming an equipartition of magnetic energy and the gravitational potential energy of accreting matter, it is possible to estimate the upper limit of the accretion rate. Assuming a black hole mass of $10M_\odot$ residing at the center, we find this to be at the most ${\dot M} = (8.5 \pm 1.4) \times 10^{-11} M_\odot$ yr$^{-1}$. This is consistent with earlier estimates of accretion rates based on optical and X-ray observations.