Observing Supernova Neutrino Light Curves with Super-Kamiokande. III. Extraction of Mass and Radius of Neutron Stars from Synthetic Data

TL;DR

This study demonstrates how neutrino observations from Super-Kamiokande can accurately determine neutron star properties like mass and radius from simulated supernova data, aiding multi-messenger astronomy.

Contribution

It introduces a method to extract neutron star mass and radius from neutrino light curves using analytical models and Monte Carlo simulations, enhancing supernova analysis techniques.

Findings

Neutrino data can determine neutron star mass within 0.1 solar masses.

Neutrino data can estimate neutron star radius within 1 km.

Total energy of the neutron star can be measured within 10^51 erg.

Abstract

Neutrinos are guaranteed to be observable from the next galactic supernova (SN). Optical light and gravitational waves are also observable, but may be difficult to observe if the location of the SN in the galaxy or the details of the explosion are unsuitable. The key to observing the next supernova is to first use neutrinos to understand various physical quantities and then link them to other signals. In this paper, we present Monte Carlo sampling calculations of neutrino events from galactic supernova explosions observed with Super-Kamiokande. The analytical solution of neutrino emission, which represents the long-term evolution of neutrino-light curve from supernovae, is used as a theoretical template. It gives the event rate and event spectrum through inverse beta decay interactions with explicit model parameter dependence. Parameter estimation is performed on these simulated sample data by fitting least squares using the analytical solution. The results show that the mass, radius and total energy of a remnant neutron star produced by a SN can be determined with an accuracy of $\sim 0.1M_\odot$, $\sim 1$ km, and $\sim 10^{51}$ erg, respectively, for a galactic SN at 8 kpc.