IDENTIFICATION CAMPAIGN OF SUPERNOVA REMNANT CANDIDATES IN THE MILKY WAY. I.<i>CHANDRA</i>OBSERVATION OF G308.3-1.4

Abstract

ROSAT all-sky survey (RASS) data have provided another window to search for\nsupernova remnants (SNRs). In reexamining this data archive, a list of\nunidentified extended X-ray objects have been suggested as promising SNR\ncandidate. However, most of these targets have not yet been fully explored by\nthe state-of-art X-ray observatories. For selecting a pilot target for a\nlong-term identification campaign, we have observed the brightest candidate,\nG308.3-1.4, with Chandra X-ray observatory. An incomplete shell-like X-ray\nstructure which well-correlated with the radio shell emission at 843 MHz has\nbeen revealed. The X-ray spectrum suggests the presence of a shock-heated\nplasma. All these evidences confirm G308.3-1.4 as a SNR. The brightest X-ray\npoint source detected in this field-of-view is also the one locates closest to\nthe geometrical center of G308.3-1.4, which has a soft spectrum. The intriguing\ntemporal variability and the identification of optical/infrared counterpart\nrule out the possibility of an isolated neutron star. On the other hand, the\nspectral energy distribution from Ks band to R band suggests a late-type star.\nTogether with a putative periodicity of \\sim1.4 hrs, the interesting excesses\nin V, B bands and H-alpha suggest this source as a promising candidate of a\ncompact binary survived in a supernova explosion (SN).\n