* Astronomy

PSR B0628-28 is a radio pulsar which 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 two 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 gives a luminosity (in cgs) Log Lx=30.34, which is ~350 times greater than what would be expected from the correlation between Lx-Edot.

Timing and spectral analysis of the combined Chandra and XMM-Newton archival data. (PDF)