Charge‐exchange emission in the starburst galaxies M82 and NGC3256

Abstract

Charge-exchange (CE) emission produces features which are detectable with the current X-ray instrumentation in the brightest near galaxies. We describe these aspects in the observed X-ray spectra of the star forming galaxies M82 and NGC 3256, from the Suzaku and XMM-Newton telescopes. Emission from both ions (O, C) and neutrals (Mg, Si) is recognised. We also describe how microcalorimeter instrumentation on future missions will improve CE observations.

Charge exchange in massive star‐forming regions

“…Some of these lines have also been found in extragalactic star-forming environments (starburst galaxies), and taken as evidence of charge exchange (CX) processes, associated with the cold gas and/or the cold gust, at the hot-cold interface. For instance, Ranalli et al (2008) and Ranalli (2012) found evidence for CX lines in M82 both from ions (O, C) and from neutrals (Mg, Si). In particular, Ranalli et al note that their lines could be caused by CX in highly-excited O VIII ions (0.78 keV) and neutral Mg (1.254 keV), and that this might indicate the presence of, e.g., olivine grains in the cold clouds of M82.…”