Radio Spectra of Three Supernova Remnants: G114.3+0.3, G116.5+1.1 and G116.9+0.2

Presented are new images of supernova remnants G114.3 0.3, G116.5 1.1 and G116.9 0.2 (CTB 1) at 408 MHz from the Canadian Galactic Plane Survey (CGPS). We also use the 1420 MHz images from the CGPS in a study of their 408-1420 MHz spectral indices. The flux densities at 408 MHz and 1420 MHz, corrected for flux densities from compact sources within the SNRs, are 12±6 Jy and 9.8±0.8 Jy for Gl 14.3 0.3,15.0±1.5 Jy and 10.6±0.6 Jy for G116.5 1.1, 15.0±1.5 Jy and 8.1±0.4 Jy for G116.9±0.2. The integrated flux density-based spectral indices (Sv∝v-α) areα=0.16±0.41, 0.28±0.09 and 0.49±0.09 for G114.3 0.3, G116.5 1.1 and G116.9 0.2, respectively. Their T-T plot-based spectral indices are 0.68±0.48, 0.28±0.15, and 0.48±0.04, in agreement with the integrated flux density-based spectral indices. New flux densities are derived at 2695 MHz which are significantly larger than previous values. The new 408, 1420 and 2695 MHz flux densities and published values at other frequencies, where images are not available, are fitted after correcting for contributions from compact sources, to derive their multi-frequency spectral indices.

Radio Spectra of Three Supernova Remnants: G114.3+0.3,G116.5+1.1 and G116.9+0.2