Constraining the high redshift formation of black hole seeds in nuclear star clusters with gas inflows

Understand

In this paper we explore a possible route of black hole seed formation that appeal to a model by Davies, Miller & Bellovary who considered the case of the dynamical collapse of a dense cluster of stellar black holes subjected to an inflow of gas.

• Here, we explore this case in a broad cosmological context.
• The working hypotheses are that (i) nuclear star clusters form at high redshifts in pre-galactic discs hosted in dark matter halos, providing a suitable environment for the formation of stellar black holes in their cores, (ii) major central inflows of gas occur onto these clusters due to instabilities seeded in the growing discs and/or to mergers with other gas-rich halos, and that (iii) following the inflow, stellar black holes in the core avoid ejection due to the steepening to the potential well, leading to core collapse and the formation of a massive seed of $<~ 1000\, \rm M_\odot$.
• We simulate a cosmological box tracing the build up of the dark matter halos and there embedded baryons, and explore cluster evolution with a semi-analytical model.