Neutrino Astronomy with the MACRO Detector

High-energy gamma-ray astronomy is now a well-established Ðeld, and several sources have been discovered in the region from a few gigaÈelectron volts up to several Tera electron volts. If sources involving hadronic processes exist, the production of photons would be accompanied by neutrinos too. Other possible neutrino sources could be related to the annihilation of weakly interacting, massive particles (WIMPs) at the center of galaxies with black holes. We present the results of a search for pointlike sources using 1100 upward-going muons produced by neutrino interactions in the rock below and inside the Monopole Astrophysics and Cosmic Ray Observatory (MACRO) detector in the underground Gran Sasso Laboratory. These data show no evidence of a possible neutrino pointlike source or of possible correlations between gamma-ray bursts and neutrinos. They have been used to set flux upper limits for candidate pointlike sources which are in the range 10^-14 10^-15 cm^-2 s^-1.