Neutron Star Mergers and How to Study Them

TL;DR

Neutron star mergers are key multimessenger astrophysical events that provide insights into fundamental physics, cosmic element formation, and cosmology, requiring advanced observations, coordination, and theoretical models.

Contribution

This review synthesizes current knowledge, observational signatures, detection prospects, and future needs for studying neutron star mergers in the multimessenger era.

Findings

Current detection rates and observational signatures summarized.

Key observations identified to advance understanding.

Future capabilities discussed for maximizing scientific return.

Abstract

Neutron star mergers are the canonical multimessenger events: they have been observed through photons for half a century, gravitational waves since 2017, and are likely to be sources of neutrinos and cosmic rays. Studies of these events enable unique insights into astrophysics, particles in the ultrarelativistic regime, the heavy element enrichment history through cosmic time, cosmology, dense matter, and fundamental physics. Uncovering this science requires vast observational resources, unparalleled coordination, and advancements in theory and simulation, which are constrained by our current understanding of nuclear, atomic, and astroparticle physics. This review begins with a summary of our current knowledge of these events, the expected observational signatures, and estimated detection rates for the next decade. I then present the key observations necessary to advance our understanding of these sources, followed by the broad science this enables. I close with a discussion on the necessary future capabilities to fully utilize these enigmatic sources to understand our universe.