Upper limits on neutrino fluxes from point-like sources with AMANDA-II

摘要

The AMANDA-II telescope, operated by the Ice-Cube collaboration, is currently the world's most sensitive telescope to fluxes of neutrinos from individual sources. A data sample of 4282 neutrino induced events collected in 1001 days of detector livetime during the years 20002004 have now been analyzed looking for a neutrino signal from point-like sources. A sensitivity to fluxes of nu(mu) + (nu) over bar (mu) + nu(tau) + (nu) over bar (tau) of d Phi/dE = 1.0 x 10(-10)(E/TeV)(-2) TeV-1 cm(-2) s(-1) was reached in the energy range between 1.7 TeV and 2.4 PeV. So far no statistically significant localized excess of events over the background of atmospheric neutrinos has been found, which would be ascribed to a neutrino source. However, the flux upper limits derived from the non-observation of a signal are comparable to observed fluxes of high energy gamma rays from blazars and within the range of current models for neutrino emission from selected sources. Possible constraints on these models are discussed.