Premerger phenomena in neutron-star binary coalescences

TL;DR

This paper reviews premerger phenomena in neutron-star binaries, discussing mechanisms like tidal resonances and electrodynamic interactions, and explores how these can inform our understanding of neutron-star physics and related astrophysical events.

Contribution

It provides a comprehensive review of premerger mechanisms and their implications for neutron-star physics, emphasizing multimessenger observations and theoretical constraints.

Findings

Gamma-ray precursors can constrain neutron-star equation of state.

Dynamical tides influence premerger electromagnetic signals.

Connections between premerger phenomena and post-merger gamma-ray bursts are discussed.

Abstract

A variety of high-energy events can take place in the seconds leading up to a binary neutron-star merger. Mechanisms involving tidal resonances, electrodynamic interactions, or shocks in mass-loaded wakes have been proposed as instigators of these precursors. With a view of gravitational-wave and multimessenger astrophysics more broadly, premerger observations and theory are reviewed emphasising how gamma-ray precursors and dynamical tides can constrain the neutron-star equation of state, thermodynamic microphysics, and evolutionary pathways. Connections to post-merger phenomena, notably gamma-ray bursts, are discussed together with how magnetic fields, spin and misalignment, crustal elasticity, and stratification gradients impact observables.