# Tidal Disruptions of Stars by Black Hole Remnants in Dense Star Clusters

## TL;DR

This paper investigates tidal disruption events caused by stellar-mass black holes in dense star clusters, predicting their rates, observable signatures, and potential contributions to binary formation through advanced simulations and cosmological models.

## Contribution

It provides the first detailed rate predictions and observational signatures for TDEs by stellar-mass black holes in globular clusters using state-of-the-art N-body simulations and cosmological models.

## Key findings

- TDE rates in globular clusters are significant and depend on cluster parameters.
- Predicted optical transients from these TDEs are detectable by current surveys.
- The cosmological rate peaks at roughly 25 Gpc^{-3} yr^{-1} at redshift 3.

## Abstract

In a dense stellar environment, such as the core of a globular cluster (GC), dynamical interactions with black holes (BHs) are expected to lead to a variety of astrophysical transients. Here we explore tidal disruption events (TDEs) of stars by stellar-mass BHs through collisions and close encounters. Using state-of-the-art $N$-body simulations, we show that these TDEs occur at significant rates throughout the evolution of typical GCs and we study how their relative rates relate to cluster parameters such mass and size. By incorporating a realistic cosmological model of GC formation, we predict a BH - main-sequence-star TDE rate of approximately $3\,\rm{Gpc}^{-3}\,\rm{yr}^{-1}$ in the local universe ($z<0.1$) and a cosmological rate that peaks at roughly $25\,\rm{Gpc}^{-3}\,\rm{yr}^{-1}$ for redshift 3. Furthermore, we show that the ejected mass associated with these TDEs could produce optical transients of luminosity $\sim 10^{41} - 10^{44}\rm\,erg\,s^{-1}$ with timescales of about a day to a month. These should be readily detectable by optical transient surveys such as the Zwicky Transient Facility. Finally, we comment briefly on BH - giant encounters and discuss how these events may contribute to the formation of BH - white-dwarf binaries.