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

TL;DR

This paper studies how different fluids accrete onto Reissner-Nordstrom-(anti)-de Sitter black holes with a global monopole, analyzing steady-state solutions and the impact of monopole charge on accretion rates.

Contribution

It provides new solutions for accretion flows with isothermal and polytropic equations of state on these black holes, highlighting the effect of monopole charge on accretion dynamics.

Findings

Isothermal fluids have explicit solutions at the sonic point.

Polytropic fluids lack global solutions for accretion.

Large monopole parameter suppresses maximum accretion rate.

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.