Extended radio observations of the SNR CTB 109

Abstract

Observations have been made of the SNR CTB 109 using the Westerbork Synthesis Radio Telescope at wavelengths of 49 cm and 21 cm, the Synthesis Telescope of the Dominion Radio Astrophysical Observatory at 21 cm, and the 46 m telescope of the Algonquin Radio Observatory at 4.6 cm. The spectral index of the integrated flux density of the SNR is given by alpha = 0.50 + or - 0.04; various maps are compared and show that, over the range of 4.6-49 cm, alpha does not vary across the SNR. Apart from the fact that the SNR shows an incomplete shell at both X-ray and radio wavelengths, there does not appear to be any correspondence of the finer details in the maps. There is no radio point source near to the position of the X-ray pulsar displaced by 3.6 arcmin from the center of curvature, but there is no indication, so far, that the pulsar is associated with the SNR.