Probing the incompressibility of nuclear matter at ultra-high density through the prompt collapse of asymmetric neutron star binaries

TL;DR

This study uses extensive neutron star merger simulations to investigate how nuclear incompressibility affects the prompt collapse threshold, providing a new way to constrain the properties of ultra-dense nuclear matter.

Contribution

It introduces the first detailed analysis of nuclear incompressibility's role in prompt collapse thresholds across different neutron star binary configurations.

Findings

Prompt collapse thresholds can constrain $K_{max}$ within tens of percent.

Observations can reveal hyperons or quarks inside neutron stars.

Method links gravitational wave data to nuclear matter properties.

Abstract

Using 250 neutron star merger simulations with microphysics, we explore for the first time the role of nuclear incompressibility in the prompt collapse threshold for binaries with different mass ratios. We demonstrate that observations of prompt collapse thresholds, either from binaries with two different mass ratios or with one mass ratio but combined with the knowledge of the maximum neutron star mass or compactness, will constrain the incompressibility at the maximum neutron star density, $K_{\rm max}$, to within tens of percent. This, otherwise inaccessible, measure of $K_{\rm max}$ can potentially reveal the presence of hyperons or quarks inside neutron stars.