The Pulsar Wind Nebula Torus of PSR J0538+2817 and the Origin of Pulsar Velocities

We find evidence for a faint wind nebula surrounding PSR J0538+2817 in Chandra X-Ray Observatory ACIS imaging. This object is particularly interesting, as the pulsar spin-down age is largest for any such X-ray pulsar wind nebula (PWN). If interpreted as an equatorial torus, the PWN supports the claimed association with the S147 supernova remnant and implies good alignment between the pulsar spin and space velocity. Comparison of the supernova remnant age, X-ray cooling age, and characteristic age suggests a birth spin period of >~ 130 ms. In turn, if we accept as causal the alignment of the linear and angular momenta, this places strong constraints on the origin of the "kick" at the neutron star birth.