Search for Thermal Afterglow from PSR 0656+14

Abstract

Thermal afterglow caused by transient energy releases in neutron stars could alter the X-ray pulse shape of pulsars by heating a portion of the crust so that more thermal X-rays are emitted at a particular phase. We developed a method to look for such changes in X-ray pulsars. We put a typical lower limit of 3.9 × 1031 ergs s-1 (1.4 × 1035 ergs in a 1 hr exposure) on the average excess X-ray luminosity required to see thermal afterglow from ROSAT data of PSR 0656+14 consisting of three separate observations lasting 3-5 hr. The lower limit obtained allows us to constrain the glitch parameters and the equation of state for neutron stars. In particular, a differentiation could be made between the vortex unpinning model and the starquake model for pulsar glitches if a search for thermal afterglow were performed contemporaneously with glitch observations.