Cosmic-Ray Nucleosynthesis in Galactic Interactions

Abstract

© 2019, Springer Nature Switzerland AG. It has been shown that galactic interactions and mergers can result in large-scale tidal shocks that propagate through interstellar gas. As a result, this can give rise to a new population of cosmic rays, additional to standard galactic cosmic rays present in star-forming galaxies. We investigate the impact of this tidal cosmic-ray population on the nucleosynthesis of light elements. We especially focus on extragalactic systems where lithium has been measured in gas phase but which have been disturbed by galactic interactions, namely the Small Magellanic Cloud and the M82. Moreover, we demonstrate that the presence of these tidal shock-waves may also have far reaching consequences on star-formation rate estimates and our general understanding of galactic evolution through affecting the far-infrared radio correlation.