Trans-Ejecta High-Energy Neutrino Emission from Binary Neutron Star Mergers

TL;DR

This paper estimates high-energy neutrino emission from binary neutron star mergers, suggesting neutrino detection could reveal jet properties even without electromagnetic signals, aiding understanding of such cosmic events.

Contribution

It provides the first detailed estimate of trans-ejecta neutrino emission from neutron star mergers and discusses their potential detectability with IceCube.

Findings

Neutrinos from internal shocks may be detectable within a few years.

IceCube-Gen2 will likely detect these neutrinos.

Neutrino observations can differentiate gamma-ray burst emission scenarios.

Abstract

The observations of a macronova/kilonova accompanied by gravitational waves from a binary neutron star merger (GW170817) confirmed that neutron star coalescences produce copious ejecta. The coincident gamma-ray detection implies the existence of a relativistic jet in this system. During the jet's propagation within the ejecta, high-energy photons and neutrinos can be produced. The photons are absorbed by the ejecta, while the neutrinos escape and can be detected. Here, we estimate such trans-ejecta neutrino emission, and discuss how neutrino observations could be used to differentiate between gamma-ray burst emission scenarios. We find that neutrinos from the internal shocks inside the ejecta may be detectable by IceCube within a few years of operation, and will likely be detected with IceCube-Gen2. The neutrino signals coincident with gravitational waves would enable us to reveal the physical quantities of the choked jets even without electromagnetic signals.