Growth of A Massive Black Hole Via Tidal Disruption Accretion by Seungjae Lee et al. on Wednesday 30 November

Stars that are tidally disrupted by the massive black hole (MBH) may

contribute significantly to the growth of the MBH, especially in dense nuclear

star clusters (NSCs). Yet, this tidal disruption accretion (TDA) of stars onto

the MBH has largely been overlooked compared to the gas accretion (GA) channel

in most numerical experiments until now. In this work, we implement a black

hole growth channel via TDA in the high-resolution adaptive mesh refinement

code Enzo to investigate its influence on a MBH seed's early evolution. We find

that a MBH seed grows rapidly from $10^3\,\mathrm{M}_\odot$ to $\gtrsim

10^6\,\mathrm{M}_\odot$ in 200\,Myrs in some of the tested simulations.

Compared to a MBH seed that grows only via GA, TDA can enhance the MBH's growth

rate by up to more than an order of magnitude. However, as predicted, TDA

mainly helps the early growth of the MBH (from $10^{3-4}\,\mathrm{M}_\odot$ to

$\lesssim10^{5}\,\mathrm{M}_\odot$) while the later evolution is generally

dominated by GA. We also observe that the star formation near the MBH is

suppressed when TDA is most active, sometimes with a visible cavity in gas (of

size $\sim$ a few pc) created in the vicinity of the MBH. It is because the MBH

may grow expeditiously with both GA and TDA, and the massive MBH could consume

its neighboring gas faster than being replenished by gas inflows. Our study

demonstrates the need to consider different channels of black hole accretion

that may provide clues for the existence of supermassive black holes at high

redshifts.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.02376v2