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, log L-x = 30.34, which is similar to 350 times greater than what would be expected from the correlation.