FERMI-LAT OBSERVATIONS OF SUPERNOVA REMNANTS INTERACTING WITH MOLECULAR CLOUDS: W41, MSH 17-39, AND G337.7-0.1

Abstract

We report the detection of γ-ray emission coincident with three supernova remnants (SNRs) using data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. W41, G337.7-0.1, and MSH 17-39 are SNRs known to be interacting with molecular clouds, as evidenced by observations of hydroxyl (OH) maser emission at 1720 MHz in their directions and other observational information. SNR shocks are expected to be sites of cosmic-ray acceleration, and clouds of dense material can provide effective targets for production of γ-rays from π[superscript 0]-decay. The observations reveal unresolved sources in the direction of G337.7-0.1 and MSH 17-39 and an extended source coincident with W41. We model their broadband emission (radio to γ-ray) using a simple one-zone model, and after considering scenarios in which the MeV-TeV sources originate from either π[superscript 0]-decay or leptonic emission, we conclude that the γ-rays are most likely produced through the hadronic channel.