New Look at the 'Jet' in the CTB 37A/B Supernova Remnant Complex.

摘要

Very Large Array observations of the unusual southern Galactic supernova remnant (SNR) complex near l = 348 degrees, b = 0 degrees at wavelengths of 6, 20, and 90 cm are presented. Derived continuum spectra and observed morphologies indicate that G348.5+0.1 (CTB 37A) does not have a 'jet' as reported by previous observers but is instead superposed on a second, previously unidentified SNR lying along the line of sight. This new SNR is designated G348.5-0.0 according to the usual convention. Other observers have also noted a faint, flat spectrum bridge of emission possibly connecting the G348.5+0.1/G348.5-0.0 superposition with a third nearby remnant G348.7+0.3 (CTB 37B). However, a connection appears unlikely, and we suggest that the 'bridge' merely consists of faint emission which has 'leaked' from the southeastern side of G348.7+0.3 and has no relation to the G348.5+0.1/G348.5-0.0 superposition. These new data also reveal a remarkable region of 'blown-out' emission from the southwestern part of G348.5+0.1 which most likely reflects the presence of large-scale density inhomogeneities in the interstellar medium into which the SNR shell is expanding.