Exploring the Fate of Stellar Core Collapse with Supernova Relic Neutrinos

TL;DR

This paper investigates how supernova relic neutrinos can reveal the different outcomes of stellar core collapse, such as neutron star formation or black hole creation, by analyzing fluxes and detector sensitivities.

Contribution

It introduces a method to distinguish stellar collapse outcomes using SRN fluxes and evaluates detector sensitivities for future observations.

Findings

SRN fluxes vary with collapse outcomes

Next-generation detectors can constrain collapse mixture fractions

Potential to extract astrophysical information from SRN measurements

Abstract

Core collapse of massive stars leads to different fates for various physical factors, which gives different spectra of the emitted neutrinos. We focus on the supernova relic neutrinos (SRNs) as a probe to investigate the stellar collapse fate. We present the SRN fluxes and event rate spectra at a detector for three resultant states after stellar core collapse, the typical mass neutron star, the higher mass neutron star, or the failed supernova forming a black hole, based on different nuclear equations of state. Then possible SRN fluxes are formed as mixtures of the three components. We also show the expected sensitivities at the next-generation water-based Cherenkov detectors, SK-Gd and Hyper-Kamiokande, as constraining the mixture fractions. This study provides a practical example of extracting astrophysical constraints through SRN measurement.