# Observing cosmological binary mergers with next generation neutrino and gravitational wave detectors

## TL;DR

This paper explores the potential for detecting thermal neutrinos from binary mergers using next-generation neutrino and gravitational wave detectors, enabling multi-messenger observations up to redshift 2 and providing insights into merger dynamics.

## Contribution

It proposes a multi-messenger observational strategy combining neutrino and gravitational wave data to study binary mergers and estimates expected neutrino event rates for future detectors.

## Key findings

- Expected neutrino events range from 0.1 to 10 for typical merger rates.
- Extreme merger scenarios could produce up to 100 neutrino events.
- Detection up to redshift z~0.5 is feasible with current planned detector sensitivities.

## Abstract

We discuss the potential of detecting thermal neutrinos from matter-rich binary mergers, via a decades-long multi-messenger campaign involving a Mt-scale water Cherenkov neutrino detector and one or more next generation gravitational wave detectors, capable of observing mergers up to redshift $z\sim 2$. The search of neutrinos in time-coincidence with gravitational wave detections will allow to identify single neutrinos from individual mergers above the background, and to study their distributions in energy, redshift and type (double neutron-star or neutron-star-black hole merger) of the candidate sources. We find that, for merger rates consistent with current LIGO-Virgo constraints, and for a $100~{\rm Mt\cdot yr}$ exposure, between ${\mathcal O(10^{-1})}$ and ${\mathcal O(10)}$ neutrino events are expected. For extreme cases of mergers with more than $10^{52}$ ergs emitted in $\mathrel{{\bar \nu}_e}$, the number of events can be as large as $\sim 100$, with sensitivity to mergers up to redshift $z\sim 0.5$ or so. Such scenarios can already be tested with a $10~{\rm Mt\cdot yr}$ exposure, resulting in constraints on the post-merger evolution of the systems being considered.