The Chandra Observations of the Two Pulsars PSR 0628-28 and PSR 1813-36
  PSR B0628-28 is an X-ray emitting radio pulsar which was observed with Advanced CCD Imaging Spectrometer (ACIS) on board Chandra on 2001 November 04 and on 2002 March 25 for 2000 s and 17000 s, respectively. The source countrate was 0.0111+-0.0013 cps. Making PSR B0628-28 to be the longest period X-ray emitting pulsar. The spectral distribution of counts can be described by several model fits. A blackbody fit yields a temperature kT=2.69_{-0.09}^{+0.09}x10^{6} K together with N_{H}=0.082_{-0.03}^{+0.04}x10^{22} cm^{-2} and a powerlaw fit yields a photon index of \gamma=2.65_{-0.29}^{+0.28} with a hydrogen column density of N_{H}=0.13_{-0.021}^{+0.028}x10^{22} cm^{-2}. Confirming the previous ROSAT pointed observation for PSR 1813-36, there was no positive detection from the 30ks Chandra ACIS observation on 2001 October 25. We obtained an upper limit for the countrate of 2.3x10^{-4} cps. 
Hakki Ogelman, Emre Tepedelenlioglu