X-ray-optical-radio observations of a resolved supernova remnant in NGC 6822

The supernova remnant (SNR) Ho 12, in the center of the dwarf irregular galaxy NGC 6822, was previously observed at X-ray, optical, and radio wavelengths. By using archival Chandra and ground-based optical data, we found that the SNR is spatially resolved in X-rays and optical. In addition, we obtained a similar to5" resolution radio image of the SNR. These observations provide the highest spatial resolution imaging of an X-ray -optical-radio SNR in that galaxy to date. The multiwavelength morphology, X-ray spectrum and variability, and narrowband optical imagings are consistent with an SNR. The SNR is a shell-shaped object with a diameter of about 10" (24 pc). The morphology of the SNR is consistent across the wavelengths, while the Chandra spectrum can be well fitted with a nonequilibrium ionization model with an electron temperature of 2.8 keV and a 0.3 - 7 keV luminosity of 1.6 x 10(37) ergs s(-1). The age of the SNR is estimated to be 1700 - 5800 yr.