Dark matter and dark energy accretion onto intermediate-mass black holes

TL;DR

This paper examines how different cosmological fluids, including dark matter and dark energy, accrete onto intermediate-mass black holes within globular clusters, revealing that dark matter could significantly grow black holes if it has pressure.

Contribution

It introduces the impact of dark matter pressure on black hole growth, challenging the assumption of collisionless dark matter and providing constraints on its equation of state.

Findings

Dark energy and cosmic background radiation have negligible accretion.

Dark matter with pressure can cause significant black hole growth.

Constraints on dark matter properties based on black hole mass limits.

Abstract

In this work we investigate the accretion of cosmological fluids onto an intermediate-mass black hole at the centre of a globular cluster, focusing on the influence of the parent stellar system on the accretion flow. We show that the accretion of cosmic background radiation and the so-called dark energy onto an intermediate-mass black hole is negligible. On the other hand, if cold dark matter has a nonvanishing pressure, the accretion of dark matter is large enough to increase the black hole mass well beyond the present observed upper limits. We conclude that either intermediate-mass black holes do not exist, or dark matter does not exist, or it is not strictly collisionless. In the latter case, we set a lower limit for the parameter of the cold dark matter equation of state.