Gamma-Ray Emission Revealed at the Western Edge of SNR G344.7–0.1

Abstract

Abstract We report on the investigation of a very high energy (VHE), Galactic γ-ray source recently discovered at >50 GeV using the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi). This object, 2FHL J1703.4–4145, displays a very hard >50 GeV spectrum with a photon index Γ γ  ∼ 1.2 in the 2FHL catalog and, as such, is one of the most extreme sources in the 2FHL subsample of Galactic objects. A detailed analysis of the available multiwavelength data shows that this source is located on the western edge of the supernova remnant (SNR) G344.7–0.1, along with extended TeV source, HESS J1702–420. The observations and the spectral energy distribution modeling support a scenario where this γ-ray source is the byproduct of the interaction between the SNR shock and the dense surrounding medium, with escaping cosmic rays (CRs) diffusing into the dense environment and interacting with a large local cloud, generating the observed TeV emission. If confirmed, an interaction between the SNR CRs and a nearby cloud would make 2FHL J1703.4–4145 another promising candidate for efficient particle acceleration of the 2FHL Galactic sample, following the first candidate from our previous investigation of a likely shock–cloud interaction occurring on the western edge of the Vela SNR.