Patrick Slane: Observations of pulsar wind nebulae

Pat discussed the geometry of pulsar wind nebulae (PWN), such as their jet and torus structure. The jets, for example, are due to the the fact that the wind termination shock is farther from the pulsar at equator than along the axis. The pulsar dumps energetic particles into the PWN. Where the synchrotron lifetime of the particles is comparable to the age of the supernova, a break appears in the spectrum. Energetic electrons produce both the synchrotron and inverse Compton (IC) emission observed in PWN. By measuring both emission mechanisms, using gamma-ray and X-ray observations, one can constrain the magnetic field of the nebula. The interaction between the PWN and its surrounding supernova remnant may explain why PWN seem distorted. Because PWN evolve within a supernova remnant a reverse shock "slams" into the PWN. Turbulent and asymmetric structures are due to this reverse shock. This may explain why TeV sources are offset from pulsars.