Newly confirmed and high quality candidate Galactic SNRs uncovered from the AAO/UKST HAlpha survey

TL;DR

This paper reports the discovery and confirmation of 18 new Galactic supernova remnants through optical imaging, spectroscopy, radio, and X-ray data, expanding the known population of SNRs.

Contribution

The study presents a new catalog of 18 optically identified Galactic SNRs, confirmed by spectral lines and multi-wavelength observations, including some previously undetected in radio surveys.

Findings

18 new SNRs confirmed via optical spectral lines

11 remnants show matching optical and radio structures

Detection of X-ray sources and possible pulsars associated with some remnants

Abstract

We present a catalogue of 18 new Galactic supernova remnants (SNRs) uncovered in the optical regime as filamentary emissions and extended nebulosities on images of the Anglo Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) HAlpha survey of the southern Galactic plane. Our follow-up spectral observations confirmed classical optical SNR emission lines for these 18 structures via detection of very strong [SII] at 6717 and 6731A relative to HAlpha ([SII]/HAlpha> 0.5). Morphologically, 10 of these remnants have coherent, extended arc or shell structures, while the remaining objects are more irregular in form but clearly filamentary in nature, typical of optically detected SNRs. In 11 cases there was a clear if not complete match between the optical and radio structures with H filamentary structures registered inside and along the presumed radio borders. Additionally, ROSAT X-ray sources were detected inside the optical/radio borders of 11 of these new remnants and 3 may have an associated pulsar. The multi-wavelength imaging data and spectroscopy together present strong evidence to confirm identification of 18 new, mostly senile Galactic SNRs. This includes G288.7-6.3, G315.1+2.7 and G332.5-5.6, identified only as possible remnants from preliminary radio observations. We also confirm existence of radio quiet but optically active supernova remnants.