Gamma-rays and neutrinos from the pulsar wind nebulae

Abstract

We construct the time dependent radiation model for the pulsar wind nebulae (PWNe), assuming that leptons are accelerated in resonant scattering with heavy nuclei, which are injected into the nebula by the pulsar. We calculate the equilibrium spectra of these particles inside the nebula taking into account their radiation and adiabatic energy losses. The spectra of γ-rays are compared with the observations of the PWNe emitting TeV γ-rays and predictions are made for the expected γ-ray fluxes from other PWNe. Expected neutrino fluxes and neutrino event rates in a 1 km 2 neutrino detector from these nebulae are also calculated. It is found that only the Crab Nebula, and possibly the Vela nebula and MSH15-52, can produce detectable neutrino event rates. 1. Introduction Young pulsars create relativistic winds which interact with the supernova envelopes creating the PWNe. These nebulae are filled with energetic particles which emit photons from radio up to TeV γ-rays (e.g. the nebulae around the Crab and Vela pulsars, PSR 1706-44, and PSR 1509-58). It is widely argued that this radiation is produced by leptons in the synchrotron and the inverse Compton (IC) processes. Here we investigate the radiation model for the PWNe in which not only leptons but also heavy nuclei can play important role. 2. The model The energetic pulsar, formated during the supernova explosion, can have strong influence on the evolution of expanding supernova envelope due to the supply of energy in the form of electromagnetic waves and relativistic particles. We construct the simple model for the evolution of such pulsar-supernova envelope system in order to consider the processes which turn to the production of high energy radiation (see for details of the model in [3]). This model allows to determine the main parameters of the expanding nebula as a function of time (the outer radius of the nebula, the radius of the pulsar wind shock, the magnetic field inside the nebula, density of matter).