Chandra Studies of Nonthermal Emission from Supernova Remnants and Pulsar Wind Nebulae

摘要

While supernova remnants (SNRs) have long been considered prime candidates as sources of cosmic rays,it is only recently that X-ray observations have identified several shell-type SNRs dominated by nonthermal emission,thus revealing shock-accelerated electrons with energies extending far beyond the typical thermal spectrum.Two of these SNRs have been detected as sources of VHE gamma-rays.In other remnants,discrepancies between the shock velocity and the electron temperature point to a strong cosmic ray component that has thrived at the expense of the thermal gas.Modeling of the radio.X-ray,and gamma-ray emission provides constraints on particle acceleration as well as the properties of the medium in which the mechanism prospers.