Searching for an interstellar medium association for HESS J1534-571

Abstract

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 HI⁠, and Parkes HI data towards HESSJ1534−571⁠. We trace molecular clouds in at least five velocity ranges, including clumpy interstellar medium structures near a dip in HI 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 HI dip. Modelling of the supernova evolution suggests a ∼8–24 kyr age for HESSJ1534−571 at this distance.