# Neutron Star Merger Afterglows: Population Prospects for the Gravitational Wave Era

## TL;DR

This paper models the diversity of neutron star merger afterglows expected in the gravitational wave era, analyzing how intrinsic, environmental, and observational factors influence observable properties and population characteristics.

## Contribution

It introduces a population model for neutron star merger afterglows, exploring their diversity and potential observational distributions in gravitational wave and electromagnetic signals.

## Key findings

- Predicted distributions of afterglow observables like flux and proper motion.
- Insights into how environmental and viewing angle factors affect afterglow diversity.
- Framework for interpreting future neutron star merger observations.

## Abstract

Following the historical observation of GW170817 and its electromagnetic follow-up, new neutron star merger afterglows are expected to be observed as counterparts to gravitational wave signals during the next science runs of the gravitational interferometer network. The diversity of the observed population of afterglows of these future events is subject to various factors, which are (i) intrinsic, such as the energy of the ejecta, (ii) environmental, such as the ambient medium density or (iii) observational, such as the viewing angle and distance of the source. Through prescribing a population of mergers and modelling their afterglows, we study the diversity of those events to be observed jointly in gravitational waves and electromagnetic bands. In the future, observables of detected events such as viewing angle, distance, afterglow peak flux or proper motion will form distributions which together with predictions from our study will provide insight on neutron star mergers and their environments.