Radio study of the recently discovered gamma-ray source G353.6-0.7/HESS J1731-347

DUBNER, G.; GIACANI, E.; CASTELLETTI, G.; TERRIER, R.; ACERO, F.

Bremen

Workshop; COSPAR-2010 New insights into the physics of supernova remnants and pulsar wind nebula; 2010

COSPAR

In the survey of the Galactic plane conducted with H.E.S.S., many TeV gamma-ray sources were discovered for which no clear counterpart at other wavelengths could be identified. HESS J1731-347, with its complex morphology  initially belonged to this source class. Recently however, the new shell-type supernova remnant (SNR) G353.6-0.7 was discovered on the basis of images from the SGPS (ATCA plus Parkes public survey at 1.4 GHz) and the MGPS (Molonglo survey at 843 MHz). A faint radio shell was identified positionally coinciding with the brightest hotspot of the TeV source. Recent X-ray observations covering a fraction of the radio shell, revealed nonthermal emission with a complex morphology that most likely can be interpreted as synchrotron emission from high-energy electrons accelerated by the SNR. This makes HESS J1731-347 a new object in the small but growing class of non-thermal shell-type supernova remnants with TeV emission, an important class because they can prove the role of SNRs as cosmic accelerators. We propose to image the radio shell structure at 20 cm with high sensitivity and good angular resolution.  The new image will allow us to perform a detailed comparison with the X-ray and gamma-ray data  and thus estimate acceleration efficiency at the shock and constrain physical parameters of the remnant.