Galactic Sources of High Energy Neutrinos

Abstract

The undisputed galactic origin of cosmic rays at energies below the so-called knee implies an existence of a nonthemal population of galactic objects which effectively accelerate protons and nuclei to TeV-PeV energies. The distinct signatures of these cosmic accelerators are high energy neutrinos and gamma-rays produced through hadronic interactions. While gamma-rays can be produced also by directly accelerated electrons, high energy neutrinos provide the most straightforward and unambiguous information about the nucleonic component of accelerated particles. The planned km-cube class high energy neutrino detectors are expected to be sensitive enough to provide the first astrophysically meaningful probes of potential VHE neutrino sources. This optimistic prediction is based on the recent discovery of high energy gamma-ray sources with hard energy spectra extending to 10 TeV and beyond. Amongst the best-bet candidates are two young shell-type supernova remnants - RXJ1713.7-4946 and RXJ0852.0-4622, and perhaps also two prominent plerions - the Crab Nebula and Vela X. Because of strong absorption of TeV gamma-rays, one may expect detectable neutrino fluxes also from (somewhat fainter) compact TeV gamma-ray emitters like the binary systems LS5039 and LS I+61~303, and, hopefully, from hypothetical "hidden" or "orphan" neutrino sources.