Analysis of neutrino burst from the supernova 1987A in the Large Magellanic Cloud

We analyzed the neutrino burst from the supernova 1987A detected by the Kamiokande II collaboration, and obtained the following results. (1) The total energy of antineutrinos is about 4.8×{}10⁵² ergs, which is consistent with theoretical predictions. If we take Wilson's group simulation as the theoretical model, it corresponds to the models with the progenitor mass 15M_. (2) The first two neutrino events cannot correspond to the predicted initial neutronization burst from the energetics and the duration time. (3) The duration time of the burst suggests that the electron-neutrino mass <26 eV. We also discussed implications on the explosion mechanism of the supernova.