Detection of Pulsed X-Ray Emission from XMM-Newton Observations of PSR J0538+2817
Cropper, M.; McGowan, K. E.; Kennea, J. A.; Zane, S.; Córdova, F. A.; Ho, C.; Sasseen, T.; Vestrand, W. T.
United States, United Kingdom
Abstract
We report on the XMM-Newton observations of the 143 ms pulsar PSR J0538+2817. We present evidence for the first detections of pulsed X-rays from the source at a frequency that is consistent with the predicted radio frequency. The pulse profile is broad and asymmetric, with a pulse fraction of 18%+/-3%. We find that the spectrum of the source is well-fitted with a blackbody with T∞=(2.12+0.04-0.03)×106 K and NH=2.5×1021 cm-2. The radius determined from the model fit of 1.68+/-0.05 km suggests that the emission is from a heated polar cap. A fit to the spectra with an atmospheric model reduces the inferred temperature and, hence, increases the radius of the emitting region; however, the pulsar distance determined from the fit is then smaller than the dispersion distance.