GMRT observations of four suspected Supernova Remnants near the Galactic centre

Abstract

We have observed two fields - Field I (l=3°.2, b=-1°.0) and Field II (l=356°.8,b=-0°.1)- with the Giant Metrewave Radio Telescope (GMRT) at 330 MHz. In the first field, we have studied the candidate supernova remnant (SNR) G3.1-0.6 and, based on its observed morphology, spectral index and polarization, confirmed it to be an SNR. We find this supernova to have a double ring appearance with a strip of emission on its western side passing through its centre. We have discovered two extended curved objects in the second field, which appears to be part of a large shell-like structure. It is possibly the remains of an old supernova in the region. Three suspected SNRs, G356.3-0.3, G356.6+0.1 and G357.1-0.2, detected in the MOST 843-MHz survey of the GC region appear to be located on this shell-like structure. While both G356.3-0.3 and G356.6+0.1 seem to be parts of this shell, G357.1-0.2, which has a steeper spectrum above 1 GHz, could be a background SNR seen through the region. Our H i absorption observation towards the candidate SNR G357.1-0.2 indicates that it is at a distance of more than 6 kpc from us.