Black hole formation in the context of dissipative dark matter

Abstract

Black holes with masses of $\rm 10^6-10^9~M_{\odot}$ dwell in the centers of most galaxies, but their formation mechanisms are not well known. A subdominant dissipative component of dark matter with similar properties to the ordinary baryons, known as mirror dark matter, may collapse to form massive black holes during the epoch of first galaxies formation. In this study, we explore the possibility of massive black hole formation via this alternative scenario. We perform three-dimensional cosmological simulations for four distinct halos and compare their thermal, chemical and dynamical evolution in both the ordinary and the mirror sectors. We find that the collapse of halos is significantly delayed in the mirror sector due to the lack of $\rm H_2$ cooling and only halos with masses above $ \rm \geq 10^7~ M_{\odot}$ are formed. Overall, the mass inflow rates are $\rm \geq 10^{-2}~M_{\odot}/yr$ and there is less fragmentation. This suggests that the conditions for the formation of massive objects, including black holes, are more favorable in the mirror sector.