Optical discovery and multiwavelength investigation of supernova remnant MCSNR J0512– 6707 in the Large Magellanic Cloud

Abstract

We present optical, radio and X-ray data that confirm a new supernova remnant (SNR) in the Large Magellanic Cloud (LMC) discovered using our deep H-alpha imagery. Optically, the new SNR has a somewhat filamentary morphology and a diameter of 56 x 64 arcsec (13.5 x 15.5 pc at the 49.9 kpc distance of the LMC). Spectroscopic follow-up of multiple regions show high [SII]/H-alpha emission-line ratios ranging from 0.66+/-0.02 to 0.93+/-0.01, all of which are typical of an SNR. We found radio counterparts for this object using our new Australia Telescope Compact Array (ATCA) 6cm pointed observations as well as a number of available radio surveys at 8 640 MHz, 4 850 MHz, 1 377 MHz and 843 MHz. With these combined data we provide a spectral index (alpha) = -0.5 between 843 and 8640 MHz. Both spectral line analysis and the magnetic field strength, ranging from 124 - 184 mG, suggest a dynamical age between 2,200 and 4,700 yrs. The SNR has a previously catalogued X-ray counterpart listed as HP 483 in the ROSAT Position Sensitive Proportional Counter (PSPC) catalogue.