SNR 0101-7226: a shell-type supernova remnant in the Small Magellanic Cloud with no X-ray emission.

New observations of SNR 0101-7226 in the small Magellanic Cloud (SMC) with the Australia Telescope Compact Array and the ROSAT High Resolution Imager reveal a shell-type radio remnant and no significant diffuse X-ray emission. The radio images show that the remnant consists of a thick shell with a complicated filamentary structure. The low X-ray brightness, which is at least a factor of three below that of similar supernova remnants (SNRs) in the SMC, could be explained if much of the hot gas generated by the SNR has escaped into a low-density region created by a nearby OB association. Alternatively, the temperature of the hot gas downstream of the supernova shock could be relatively low, and X-ray emission could have been largely absorbed along the line of sight. We confirm the identification of a point-like X-ray source, which is spatially coincident with SNR 0101-7226, with a Be star binary system and show that the brightness of this X-ray source is variable.