Search for new supernova remnant shells in the Galactic plane with H.E.S.S.

TL;DR

This paper reports the discovery of new supernova remnant shell candidates in the Galactic plane using H.E.S.S. gamma-ray data, highlighting their potential role in cosmic-ray acceleration and the challenges in confirming their nature.

Contribution

The study presents new TeV gamma-ray shell candidates, including one confirmed SNR, expanding the catalog of known remnants and exploring their emission mechanisms.

Findings

Identification of one new SNR shell candidate, HESS J1534-571.

Detection of several TeV shell candidates lacking lower-energy counterparts.

Discussion on the significance of hadronic processes in shell emission.

Abstract

Amongst the population of TeV gamma-ray sources detected with the High Energy Stereoscopic System (H.E.S.S.) in the Galactic plane, clearly identified supernova remnant (SNR) shells constitute a small but precious source class. TeV-selected SNRs are prime candidates for sources of efficient cosmic-ray acceleration. In this work, we present new SNR candidates that have been identified in the entire H.E.S.S. phase I data set of the Galactic plane recorded over the past ten years. Identification with a known SNR shell candidate was successful for one new source, HESS J1534-571. In other cases, TeV-only shell candidates are challenging to firmly identify as SNRs due to their lack of detected non-thermal emission in lower energy bands. We will discuss how these objects may present an important link between young and evolved SNRs, since their shell emission may be dominated by hadronic processes.