X-ray emission from giant H II regions in M101

We have examined the archival ROSAT Position Sensitive Proportional Counter (PSPC) and the High-Resolution Imager (HRI) images of the galaxy M101 to study the X-ray properties of its giant H II regions. All five giant H II regions, NGC 5447, NGC 5445, NGC 5461, NGC 5462, and NGC 5471, show X-ray emission. By observing their basic properties, such as size, hardness ratio, and estimated luminosity, and by comparisons with better known regions in the Large Magellanic Cloud (LMC), we are able to suggest some possible mechanisms for the sources of the X-ray emission.