2016MNRAS.457.4262H

We report the results from a detailed γ-ray investigation in the field of two 'dark accelerators', HESS J1745-303 and HESS J1741-302, with 6.9 yr of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we found that its MeV-GeV emission is mainly originated from the 'Region A' of the TeV feature. Its γ-ray spectrum can be modelled with a single power law with a photon index of Γ ∼ 2.5 from few hundreds MeV-TeV. Moreover, an elongated feature, which extends from 'Region A' towards north-west for ∼13, is discovered for the first time. The orientation of this feature is similar to that of a large-scale atomic/molecular gas distribution. For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for this unidentified TeV source. On the other hand, we have detected a new point source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved which resembles that of a γ-ray pulsar. This makes it possibly associated with PSR B1737-20 or PSR J1739-3023.