Fermi-LAT Observations of Supernova Remnant G5.7-0.1, Believed to be Interacting with Molecular Clouds

Abstract

This work reports on the detection of γ-ray emission coincident with the supernova remnant (SNR) G5.7-0.1 using data collected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The SNR is believed to be interacting with molecular clouds, based on 1720 MHz hydroxyl (OH) maser emission observations in its direction. This interaction is expected to provide targets for the production of γ-ray emission from π⁰-decay. A γ-ray source was observed in the direction of SNR G5.7-0.1, positioned near the bright γ-ray source SNR W28. We model the emission from radio to γ-ray energies using a one-zone model. Following consideration of both π⁰-decay and leptonically dominated emission scenarios for the MeV-TeV source, we conclude that a considerable component of the γ-ray emission must originate from the π⁰-decay channel. Finally, constraints were placed on the reported ambiguity of the SNR distance through X-ray column density measurements made using XMM-Newton observations. We conclude G5.7-0.1 is a significant γ-ray source positioned at a distance of ∼3 kpc with luminosity in the 0.1-100 GeV range of L_γ ≈ 7.4 × 10³⁴ erg s^-1.