2009ApJ...699..507Z

Observations indicate that there is a pulsar in CTA 1 and the pulsar powers a synchrotron pulsar wind nebula (PWN) embedded in a larger supernova remnant. We investigate high-energy photon emission from the CTA 1 in such a case. The emission is divided into pulsed and unpulsed components. For the pulsed emission, we calculate the gamma-ray spectrum in the vacuum outer gap model. For the unpulsed component, we calculate the spectra of nonthermal photons produced in the PWN on the frame of time-dependent pulsar wind model. Our results indicate that high-energy gamma rays are dominated by those produced in the pulsar (i.e., the pulsed component is dominant), but very high energy gamma rays are dominated by those produced in the PWN and will be detected by VERITAS, although the CTA 1 is a weaker TeV emitter.