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.