  We report the detection of gamma-ray emission coincident with three supernova
remnants (SNRs) using data from the Large Area Telescope on board the Fermi
Gamma-ray Space Telescope. W41, MSH 17-39, and G337.0-0.1 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
gamma-rays from neutral pion-decay. The observations reveal unresolved sources
in the direction of G337.0-0.1, and MSH 17-39, and an extended source
coincident with W41. We model their broadband emission (radio to gamma-ray)
using a simple one-zone model, and after considering scenarios in which the
MeV-TeV sources originate from either neutral pion-decay or leptonic emission,
we conclude that the gamma-rays are most likely produced through the hadronic
channel.

High Energy Astrophysical Phenomena