Investigation of CTA 1 using a Suzaku observation
Enoto, Teruaki; Kong, Albert K. H.; Hui, C. Y.; Shibata, Shinpei; Takata, Jumpei; Lin, Lupin C. C.; Chang, H. K.; Huang, Regina H. H.; Liang, J. S.; Hwang, C. Y.
Taiwan, Hong Kong SAR, South Korea, Japan
Abstract
We report on a 105-ks Suzaku observation (obsid 404011010 with J. Takata as PI) of the supernova remnant CTA 1 (G119.5+10.2). The Suzaku soft X-ray observation was carried out using both the timing and imaging modes. A ∼10-arcmin extended feature, which is interpreted as a bow-shock component of the pulsar wind nebula, is revealed in this deep observation for the first time. The nebular spectrum can be modelled by a power law with a photon index of ∼1.8, which suggests a slow synchrotron cooling scenario. The photon index is approximately constant across this extended feature. We compare our observations of this complex nebula with previous X-ray investigations, and we discuss our findings. We do not obtain any significant pulsation from the central pulsar in the soft (0.2-12 keV) and hard (10-60 keV) X-ray data. The non-detection is mainly a result of the loss of the precise imaging ability to accurately determine the source contribution. The spectra from the X-ray imaging spectrometer and the hard X-ray detector can be directly connected without a significant spectral break, according to our analysis. Future observations by the Nuclear Spectroscopic Telescope Array (NuSTAR) and Astro-H might be able to resolve the contamination and provide an accurate hard X-ray measurement of CTA 1.