Search for supernova bursts in Super-Kamiokande IV

TL;DR

This paper reports on a decade-long search for distant supernova neutrino bursts using Super-Kamiokande IV data, setting upper limits on supernova rates out to 100-300 kpc, but finds no evidence of such events.

Contribution

It introduces an offline analysis method to detect distant supernovae in Super-Kamiokande data, extending the search beyond real-time detection capabilities.

Findings

No supernova bursts detected in 2008-2018 data.

Established upper limits on supernova rates out to 100 and 300 kpc.

Set constraints on black hole-forming supernovae occurrence.

Abstract

Super-Kamiokande has been searching for neutrino bursts characteristic of core-collapse supernovae continuously, in real time, since the start of operations in 1996. The present work focuses on detecting more distant supernovae whose event rate may be too small to trigger in real time, but may be identified using an offline approach. The analysis of data collected from 2008 to 2018 found no evidence of distant supernovae bursts. This establishes an upper limit of 0.29 year$^{-1}$ on the rate of core-collapse supernovae out to 100 kpc at 90% C.L.. For supernovae that fail to explode and collapse directly to black holes the limit reaches to 300 kpc.