# Neutron Star Merger Remnants: Braking Indices, Gravitational Waves, and the Equation Of State

## TL;DR

This paper reviews the role of millisecond magnetars formed after neutron star mergers in explaining x-ray afterglows, gravitational-wave emissions, and constraining the nuclear matter equation of state.

## Contribution

It provides a comprehensive review of the current understanding of millisecond magnetars in short gamma-ray bursts, focusing on their observational signatures and implications for nuclear physics.

## Key findings

- Magnetars may explain x-ray plateaus in short gamma-ray bursts.
- Potential gravitational-wave signals from these remnants are discussed.
- Current and future measurements could constrain the nuclear matter equation of state.

## Abstract

The binary neutron star merger GW170817/GRB170817A confirmed that at least some neutron star mergers are the progenitors of short gamma-ray bursts. Many short gamma-ray bursts have long-term x-ray afterglows that have been interpreted in terms of post-merger millisecond magnetars---rapidly rotating, highly magnetised, massive neutron stars. We review our current understanding of millisecond magnetars born in short gamma-ray bursts, focusing particularly three main topics. First, whether millisecond magnetars really do provide the most plausible explain for the x-ray plateau. Second, determining and observing the gravitational-wave emission from these remnants. Third, determining the equation of state of nuclear matter from current and future x-ray and gravitational-wave measurements.