2018MNRAS.480..134M

The Galactic supernova remnant HESSJ1534- 571 (also known as G323.7 - 1.0) has a shell-like morphology in TeV gamma-ray emission and is a key object in the study of cosmic ray origin. Little is known about its distance and local environment. We examine Mopra ¹²CO/¹³CO(1-0) data, Australian Telescope Compact Array H I, and Parkes H I data towards HESSJ1534- 571. We trace molecular clouds in at least five velocity ranges, including clumpy interstellar medium structures near a dip in H I emission at a kinematic velocity consistent with the Scutum-Crux arm at ∼3.5 kpc. This feature may be a cavity blown-out by the progenitor star, a scenario that suggests HESSJ1534- 571 resulted from a core-collapse event. By employing parametrizations fitted to a sample of supernova remnants of known distance, we find that the radio continuum brightness of HESSJ1534- 571 is consistent with the ∼3.5 kpc kinematic distance of the Scutum-Crux arm H I dip. Modelling of the supernova evolution suggests a ∼8-24 kyr age for HESSJ1534- 571 at this distance.