G337.2+0.1: A new X-ray supernova remnant?

Abstract

We present evidence supporting a SNR origin for the radio source G337.2+0.1, which was discovered along the line of sight to the Norma spiral arm in the MOST 843-MHz radio survey. The radio source is spatially superposed to the unidentified ASCA source AX J1635.9-4719. An analysis of this latter source reveals that its X-ray spectrum, extended nature, and non-variable flux are consistent with what is expected for a SNR. In addition, we have used HI-line observations of the region to look for any effect of the presumed remnant on the ISM. We have found a well-defined minimum centered at the position of the radio source in the velocity range of ∼−25 to −19 km s−1. This feature appears as a sharp absorption dip in the spectrum that might be produced when the continuum emission from the SNR candidate is absorbed by foreground gas. Hence we have used it to constrain the distance to the source, which seems to be a young (age ∼ a few 103 yr) and distant (d ∼ 14 kpc) SNR. G337.2+0.1 and AX J1635.9-4719 would be the radio/X-ray manifestations of this remnant.