Chandra and XMM-Newton Observations of the Exceptional Pulsar B0628-28

Abstract

PSR B0628-28 is a radio pulsar that was first detected in the X-ray band by ROSAT and then later observed with Chandra and XMM-Newton. The Chandra observation yielded an X-ray luminosity 2 orders of magnitude higher than what is expected for spin-powered pulsars; also, there were no pulsations detected. The XMM-Newton observation, however, reveals pulsations at the expected radio period, P=1.244 s. The simultaneously analyzed spectra also give a luminosity (in cgs) of logL_X=30.34, which is ~350 times greater than what would be expected from the L_X-E˙ correlation.