2021/01/31 by Alexei V. Ivlev, Kedron Silsbee, Marco Padovani +1 · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/abdc27
Accepted to ApJ
arxiv created 2021/02/09 · arxiv updated 2021/03/17
The energy spectrum of electrons produced in molecular gas by interstellar cosmic rays (CRs) is rigorously calculated as a function of gas column density N traversed by the CRs. This allows us to accurately compute the local value of the secondary ionization rate of molecular hydrogen, ζ\rm sec(N), as a function of the local primary ionization rate, ζp(N). The ratio ζ\rm sec/ζp increases monotonically with N, and can considerably exceed the value of ≈0.67 commonly adopted in the literature. For sufficiently soft interstellar spectra, the dependence ζ\rm sec/ζp versus N is practically insensitive to their particular shape and thus is a general characteristic of the secondary CR ionization in dense gas.