SN 1987A: Historical view about registration of the neutrino signal with Baksan, KAMIOKANDE II and IMB detectors

The detection of neutrinos from SN 1987A opened a new era in neutrino astrophysics in the last century. We present a historical view about registration of the neutrino signal from supernova SN 1987A in the Large Magellanic Cloud by the BAKSAN liquid scintillator detector and by the two water Cherenkov detectors — Kamiokande-II and IMB. All three detectors observed a total neutrino signal of 24 events at 7:35 UT 23 February, 1987. I will concentrate mostly about the BAKSAN supernova group analysis of the neutrino signal, which was already done in the years 1987 and 1988. The results of this analysis (determination of average properties of the neutrino signal: the total energy of neutrino emission, the effective neutrino temperature, the total luminosity of the neutrino signal, duration of the neutrino burst) are presented. The common analysis of all three detectors shows that these 'parameters' have good agreement with the general theoretical description of explosions of supernovae. The analysis shows that the inclusion of the BAKSAN data is very important for the understanding of the SN87A event. The latest results of 20 years of observation of our Galaxy by the BAKSAN scintillation telescope show that the upper limit of the mean frequency of gravitational collapses is <0.13 yr^-1 at a 90% confidence level

SOLAR AND SUPERNOVA CONSTRAINTS ON COSMOLOGICALLY INTERESTING NEUTRINOS

The sun and core-collapse supernovae produce neutrino spectra that are sensitive to the effects of masses and mixing. Current results from solar neutrino experiments provide perhaps our best evidence for such new neutrino physics, beyond the standard electroweak model. I discuss this evidence as well as the limited possibilities for more conventional explanations. If the resolution of the solar neutrino problem is νe → νµ oscillations, standard seesaw estimates of mντ suggest a cosmologically interesting third-generation neutrino. I discuss recent nucleosynthesis arguments that lead to an important constraint on this possibility. 1 I