Search for neutrino point sources in the southern sky hemisphere

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We search for celetial neutrino point sources in the southern sky hemisphere by neutrino induced upward-going muon detected with the Super-Kamiokande detector. Search for neutirno signal from active galactic nuclei (AGN) is particularly interesting. The major background of atmosperic neutrino origin below 100 GeV is estimated to be 0.05 events/year. We have accumulated approximately 2000 neutirino induced upward-going muon events during 1600 detector live days from 1996 to 2001. We perform a Monte Carlo simulation as well as an analytic calculation of neutrino events, assuming AGN neutrino sources. Other analysis software are developed whenever needed. We spend our time extensively on the development of an automatic event reconstruction program of through-going and stopping muons in the Super-Kamiokande detector. The expected number of upward-going muons induced by atmospheric neutrinos is estimated to be roughly 2000 events which is reasonably consistent with the observed number. We plot the observed upward-going muon events in the celestial coordinates and study the event density distribution. We check whether there exists excess of upward-going events from acelecial point sources againt the atmospheric neutrino background events. However, we find no statistically significant excess in the southern sky hemisphere. Accordingly, we set the most stringent upper limit of 10^<-14>/cm^2/s at 90% confidence level on neutrino-induced upward-going muons from celetial point sources.