Accretion on Reissner-Nordstrom-(anti)-de Sitter Black Hole with Global Monopole

Abstract

In this paper, we investigate the accretion on the Reissner-Nordstr\"{o}m anti-de-Sitter black hole with global monopole charge. We discuss the general solutions of accretion using the isothermal and polytropic equations of state for steady state, spherically symmetric, non-rotating accretion on the black hole. In the case of isothermal flow, we consider some specific fluids and derive their solutions at the sonic point as well. However, in case of polytropic fluid we calculate the general expressions only, as there exists no global (Bondi) solutions for polytropic test fluids. In addition to this, the effect of fluid on the mass accretion rate are also studied. Moreover, the large monopole parameter $\beta$ greatly suppresses the maximum accretion rate.