Speaker: Roger Chevalier (UVA)

Title: Pulsar power: the beating heart of supernovae

Abstract: The association of the Crab Pulsar with the Crab Nebula showed that pulsars (rotating neutron stars) form in supernova explosions and that their spindown powers aspects of the nebula. The basic features of the synchrotron emitting nebula in the Crab can be understood in terms of a relativistic wind that passes through a shock front and decelerates out to the outer shell of the pulsar nebula.  Particle transport is by advection with the magnetic field and diffusion.  The shell is accelerated by the wind bubble, leading to Rayleigh-Taylor instabilities and filamentary nebular structure. In cases where the energy input by the pulsar is comparable to the supernova energy, blowout of the pulsar nebula can occur, which could apply to the Crab and some superluminous supernovae.  In later evolutionary phases, the interaction with the surrounding medium drives a shock wave back into the pulsar nebula, crushing it and displacing it from the pulsar. 

Short Bio: Roger Chevalier is the W. H. Vanderbilt Professor of Astronomy at the University of Virginia. After obtaining his Ph.D from Princeton University in 1973, he joined the scientific staff of Kitt Peak National Observatory in Tucson, Arizona.  He moved to the University of Virginia in 1979, where his research has centered on theoretical studies of rapidly expanding astronomical sources, including supernovae, supernova remnants, gamma-ray bursts, pulsar wind nebulae, and galactic superwinds.  His honors include the Dannie Heineman Prize for Astrophysics (1996) and election to the National Academy of Sciences (1996).