New high-resolution radio observations of the Supernova Remnant CTB 80

Abstract

We report new high-resolution and high-sensitivity radio observations of the extended supernova remnant (SNR) CTB 80 (G69.0+2.7) at 240, 324, 618, and 1380 MHz. The imaging of CTB 80 at 240 and 618 MHz was performed using the Giant Metrewave Radio Telescope in India. The observations at 324 and 1380 MHz were obtained using the Very Large Array of the National Radio Astronomy Observatory in its C and D configurations. The new radio images reveal faint extensions for the asymmetric arms of CTB 80. The arms are irregular, with filaments and clumps of size 1' (or 0.6 pc at a distance of 2 kpc). The radio image at 1380 MHz is compared with IR and optical emission. The IR-radio correspondence is excellent along the north arm of CTB 80. Ionized gas observed in the [S II] line perfectly matches the west and north edges of CTB 80. The central nebula associated with the pulsar PSR B1951+32 was investigated with an angular resolution of 10'' × 6''. The new radio image obtained at 618 MHz shows with superb detail structures in the 8' × 4' east-west "plateau" nebula that hosts the pulsar on its western extreme. A twisted filament, about 6' in extent (~3.5 pc), trails behind the pulsar in an approximate west-east direction. In the bright "core" nebula (size ~ 45''), located to the west of the plateau, the images show a distortion in the morphology toward the west; this feature corresponds to the direction in which the pulsar escapes from the SNR with a velocity of ~240 km s^-1. Based on the new observations, the energetics of the SNR and of the pulsar wind nebula are investigated.