X‐Ray Observations of the Compact Source in CTA 1

Abstract

We have studied the point source RX J0007.0+7302, at the center of supernova remnant CTA 1, using the X-Ray Multi-mirror Mission (XMM-Newton). The X-ray spectrum of the source is consistent with that of a neutron star and is well described by a power law with the addition of a soft thermal component that may correspond to emission from hot polar cap regions or to cooling emission from a light-element atmosphere over the entire star. There is evidence of extended emission on small spatial scales, which may correspond to structure in the underlying synchrotron nebula. No pulsations are observed. Extrapolation of the nonthermal spectrum of RX J0007.0+7302 to gamma-ray energies yields a flux consistent with that of EGRET source 3EG J0010+7309, supporting the proposition that there is a gamma-ray-emitting pulsar at the center of CTA 1. Observations of the outer regions of CTA 1 with ASCA confirm earlier detections of thermal emission from the supernova remnant and show that the synchrotron nebula extends to the outermost reaches of the remnant.