Search for High-Energy Neutrinos from SN1987A: First Six Months

Upward-going muons with energy greater than 1.7 GeV produced in the nearby rock by neutrinos from SN1987A were searched for in a 2140-ton underground water Cherenkov detector, Kamiokande II. No upward-going muons from the direction of SN1987A were found from 23 February 1987 to 1 September 1987; the 90%-confidence-level flux limit is 1.2×${10}^{-13\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{s}}^{-1\mathrm{}}$ for an energy threshold of 1.7 GeV. For neutrino energy greater than 1.7 GeV, limits on the SN1987A neutrino flux and luminosity are 2.4×${10}^{-5\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{s}}^{-1\mathrm{}}$ and 1.6×${10}^{41}$ erg ${\mathrm{s}}^{-1\mathrm{}}$ for cutoff energy $E_c={10}^{15}$ eV and spectral index $\gamma =2.1, \mathrm{and} 2.3\times {10}^{-3\mathrm{}} {\mathrm{cm}}^{-2\mathrm{}} {\mathrm{s}}^{-1\mathrm{}} \mathrm{and} 4.6\times {10}^{42} \mathrm{erg} {\mathrm{s}}^{-1\mathrm{}}$ for $E_c={10}^{12}$ eV and $\gamma =2.7\mathrm{}$.