# Tidal disruption event rates in galaxy merger remnants

## TL;DR

This study investigates how galaxy mergers influence tidal disruption event rates by analyzing high-resolution simulations, revealing that starbursts can temporarily boost TDE rates around secondary black holes, while primary black holes remain unaffected.

## Contribution

It provides the first detailed analysis of TDE rate evolution during galaxy mergers using high-resolution hydrodynamical simulations combined with loss-cone theory estimates.

## Key findings

- Starbursts increase TDE rates around secondary black holes.
- TDE rates around primary black holes remain constant.
- Post-binary formation, TDE rates decline as stellar density decreases.

## Abstract

The rate of tidal disruption events (TDEs) depends sensitively on the stellar properties of the central galactic regions. Simulations show that galaxy mergers cause gas inflows, triggering nuclear starbursts, increasing the central stellar density. Motivated by these numerical results, and by the observed over-representation of post-starburst galaxies among TDE hosts, we study the evolution of the TDE rate in high-resolution hydrodynamical simulations of a galaxy merger, in which we capture the evolution of the stellar density around the massive black holes (BHs). We apply analytical estimates of the loss-cone theory, using the stellar density profiles from simulations, to estimate the time evolution of the TDE rate. At the second pericentre, a nuclear starburst enhances the stellar density around the BH in the least massive galaxy, leading to an enhancement of the TDE rate around the secondary BH, although the magnitude and the duration of the increase depend on the stochasticity of star formation on very small scales. The central stellar density around the primary BH remains instead fairly constant, and so is its TDE rate. After the formation of the binary, the stellar density decreases, and so does the TDE rate.