Northern disk of M31 XMM-Newton images

The brightest emission regions were found to be correlated with populations of massive stars, notably in the 10kpc star-forming ring. The plasma temperatures in the ring regions are ~0.2keV up to ~0.6keV. We suggest this emission is hot ISM heated in massive stellar clusters and superbubbles.

We derived X-ray luminosities, densities, and pressures for the gas in each region. We also found large extended emission filling low density gaps in the dust morphology of the northern disk, notably between the 5kpc and 10kpc star-forming rings. We propose that the hot gas was heated and expelled into the gaps by the populations of massive stars in the rings.

It is clear that the massive stellar populations are responsible for heating the ISM to X-ray emitting temperatures, filling their surroundings, and possibly driving the hot gas into the low density regions. Overall, the morphology and spectra of the hot gas in the northern disk of M 31 is similar to other galaxy disks.