γ-Ray emission from PWNe interacting with molecular clouds

Abstract

We consider a situation in which a pulsar is formed inside or close to a high-density region of a molecular cloud. Right after birth, the pulsar was very active and accelerated hadrons and leptons to very high energies. Hadrons diffuse through the supernova remnant and some of them are trapped in the nearby cloud interacting with the matter. We extend a recent time-dependent model for the γ radiation of pulsar wind nebulae (PWNe) to describe this more complicated astrophysical scenario. The typical calculations have been performed for two objects, IC 443 and W41, which have recently been discovered as sources of TeV γ-rays. In this model the low-energy TeV emission should be correlated with the birth place of the pulsar and the region of dense soft radiation rather than with its present position, provided that the injection rate of relativistic particles into the PWN has been much more efficient at early times. The high-energy TeV emission should be correlated with the location of dense clouds which were able to capture high-energy hadrons due to their strong magnetic fields. © 2008 RAS.