Detection of an X-ray pulsation for the Gamma-ray pulsar centered in CTA 1

We report the detection of X-ray pulsations with a period of ∼315.87 ms from the 2009 XMM-Newton observation for the radio-quiet γ -ray pulsar, LAT PSR J0007+7303, centered in the supernova remnant CTA 1. The detected pulsed period is consistent with the γ -ray periodicity at the same epoch found with the Fermi Gamma-ray Space Telescope. The broader sinusoidal structure in the folded light curve of the X-ray emission is dissimilar to that of the γ -ray emission, and the phase of the peak is about 0.5 shifting from the peak in the γ -ray bands, indicating that the main component of the X-rays originates from different sites of the pulsar. We conclude that the main component of the X-ray pulsation is contributed by the thermal emission from the neutron star. Although with a significantly different characteristic age, PSR J0007+7303 is similar to Geminga in emission properties of X-rays and γ -rays; this makes PSR J0007+7303 the second radio-quiet γ -ray pulsar with detected X-ray pulsations after Geminga.