Charge exchange in massive star-forming regions

As a result of feedback from massive stars, via their intense winds and/or supernova explosions, massive star-forming regions are entirely filled with hot, X-ray emitting plasmas, which escape into the ambient ISM. As shown recently by Townsley et al. for several "extreme" cases (Carina, M17, NGC 3576, NGC 3603, 30 Dor), by way of large Chandra ACIS mosaics, extra, non-thermal emission lines are present on top of the standard lines emitted by hot plasmas. Some of them are very close to lines characteristic of charge-exchange reactions between the hot plasma and the cold surrounding material, suggesting that this mechanism operates on large spatial scales (several 10 pc) in star-forming regions in general. The connection with starburst galaxies is briefly mentioned, and it is pointed out that supernovae interacting with molecular clouds may also provide a good environment to look for charge exchange processes.