Variability of the Vela Pulsar Wind Nebula Observed with Chandra

The observations of the pulsar wind nebula (PWN) around the Vela pulsar with the Advanced CCD Imaging Spectrometer aboard the Chandra X-Ray Observatory, taken on 2000 April 30 and November 30, reveal its complex morphology reminiscent of that of the Crab PWN. Comparison of the two observations shows changes up to 30% in the surface brightness of the PWN features. Some of the PWN elements show appreciable shifts, up to a few arcseconds (~1016 cm), and/or spectral changes. Such variations hold the potential to provide a new diagnostics for the study of PWNe.