X-ray emission properties of the old pulsar PSR B2224+65

Using archival Chandra data we studied the X-ray emission properties of PSR B2224+65 and its environment. Albeit limited by photon statistics the spectral analysis suggests that the bulk of the emission from PSR B2224+65 is non-thermal. Fitting a power-law model to the observed energy spectrum yields a photon index of Gamma = 1.58(-0.33)(+0.43). The possible origin of the non- thermal pulsar emission is discussed in the context of the outer- gap model. We did not find any evidence for a compact nebula around PSR B2224+65 though the Chandra data reveal the existence of an extended feature which appears to be associated with PSR B2224+65. It extends from the pulsar position about 2 arcmin to the north- west. Its orientation deviates by similar to 118 degrees from the pulsar's proper motion direction. Investigating its energy spectrum shows that the emission of this extended feature is much harder than that of the pulsar itself and is non- thermal in nature.