# Merger estimates for Kerr-Sen black holes

## TL;DR

This paper analyzes Kerr-Sen black hole mergers within string theory, estimating final spins and quasinormal modes to aid gravitational wave tests of alternative gravity models.

## Contribution

It provides the first estimates of merger outcomes for Kerr-Sen black holes, extending gravitational wave analysis to string-inspired black hole solutions.

## Key findings

- Approximate final spins of Kerr-Sen black hole mergers.
- Quasinormal mode spectra for Kerr-Sen black holes.
- Implications for gravitational wave observations.

## Abstract

The advent of gravitational wave observation starts a new era of precision tests of gravitational theory. Estimations of black holes mergers should come from any well established gravitational theories, provided that the theory has not been ruled out by observations. In this paper we consider the low energy limit of heterotic string theory where the associated rotating and charged black holes are described by the Kerr-Sen solution. We investigate the approximate final spins and quasinormal modes of the black hole resulting from the merger process.