Non-thermal emission from massive star forming regions: A possible SNR candidate G351.7-1.2?

We present low frequency wide band observations (300-500 MHz) of the star forming complex G351.7-1.2 using upgraded Giant Metrewave Radio Telescope (uGMRT), India. Combining this with the optical, infrared and submillimeter data, we analyse the large scale diffuse radio emission associated with the region that exhibits a broken shell morphology. The spectral index of the emission in the shell is -0.8, indicating non-thermal emission. H-alpha emission that mimics the morphology of the radio shell on a smaller scale is also detected here. Based on the non-thermal emission from the radio shell and the presence of its optical counterpart, we classify G351.7-1.2 as a candidate SNR. A gamma-ray source detected by Fermi LAT (1FGLJ1729.1-3641c) is located towards the south-west of the radio shell and could have a possible origin in the interaction between high velocity particles from the SNR and the ambient molecular cloud.
Comment: 12 pages, 11 figures, accepted for publication in MNRAS