Multiband Non-Thermal Radiation from the Crab Nebula and the Pulsar Wind Nebula in MSH 15-52

We study the multiband non-thermal emission from two pulsar wind nebulae (PWNe), the Crab nebula and the PWN in MSH 15-52. Both of them have been recently detected by the Fermi large area telescope (LAT) and powered by central gamma-ray pulsars. Motivated by the Fermi LAT results, we use a simplified time-dependent injection model to study the non-thermal emission from radio to very high energy gamma-ray radiation from these two sources. In this model, the relativistic electrons are accelerated in pulsar magnetosphere and at pulsar wind termination shocks and can be described by a broken power law. Those high energy particles evolve with time and produce non-thermal emission through synchrotron radiation and inverse Compton scattering of soft photons. For Crab nebula, using the GeV emission from 100 MeV to 10 GeV given by Fermi LAT, we can constrain the maximum energy of the electrons and other parameters. The non-thermal emission can be well explained by this model. We also use this model to explain the non-thermal emission from the PWN in MSH 15-52.