Search for Supernova Neutrino Bursts at Super-Kamiokande

TL;DR

This study used the Super-Kamiokande detector to search for neutrino bursts from supernovae within our galaxy and nearby regions, finding no such events over several years but setting limits on supernova rates.

Contribution

It provides the first extensive search for supernova neutrino bursts with Super-Kamiokande, establishing upper limits on supernova rates in our galaxy and nearby galaxies.

Findings

No supernova neutrino bursts detected during the observation period.

Set a 90% confidence level upper limit of 0.32 supernovae per year within 100 kiloparsecs.

Demonstrated the detector's high efficiency for supernova neutrino detection.

Abstract

The result of a search for neutrino bursts from supernova explosions using the Super-Kamiokande detector is reported. Super-Kamiokande is sensitive to core-collapse supernova explosions via observation of their neutrino emissions. The expected number of events comprising such a burst is ~10^4 and the average energy of the neutrinos is in few tens of MeV range in the case of a core-collapse supernova explosion at the typical distance in our galaxy (10 kiloparsecs); this large signal means that the detection efficiency anywhere within our galaxy and well past the Magellanic Clouds is 100%. We examined a data set which was taken from May, 1996 to July, 2001 and from December, 2002 to October, 2005 corresponding to 2589.2 live days. However, there is no evidence of such a supernova explosion during the data-taking period. The 90% C.L. upper limit on the rate of core-collapse supernova explosions out to distances of 100 kiloparsecs is found to be 0.32 SN/year.