Speaker
Description
After the observation of SN 1987A, neutrino astronomy was started. Supernova neutrinos give us information about the mechanism of supernova explosion, and even about the property of the neutrino. Therefore, various neutrino detectors have been searched for supernova neutrino events for about 40 years.
In this presentation, we show the results of a search for core-collapse supernova neutrinos. We use KamLAND data during about 18 years: from 2002 March 9 to 2020 April 25. The neutrino energy range we searched is 1.8 MeV–111 MeV. As a result, we find no neutrino clusters and give the upper limit on the supernova rate to be 0.15 $\mathrm{yr}^{−1}$ with a 90% confidence level. We estimate the detectable range, which corresponds to a >95% detection probability. That value is 40–59 kpc and 65–81 kpc for core-collapse supernovae and failed core-collapse supernovae, respectively. We also propose to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is <(17.5–22.7) $M_{\odot} \mathrm{yr}^{−1}$ with a 90% confidence level.
