Ivlev, Alexei V.Alexei V.IvlevSilsbee, KedronKedronSilsbeePADOVANI, MarcoMarcoPADOVANIGALLI, DanieleDanieleGALLI2024-01-242024-01-2420210004-637Xhttp://hdl.handle.net/20.500.12386/34610The 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, ${\zeta }_{\sec }(N)$ , as a function of the local primary ionization rate, ζ<SUB>p</SUB>(N). The ratio ${\zeta }_{\sec }/{\zeta }_{p}$ 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 ${\zeta }_{\sec }/{\zeta }_{p}$ versus N is practically insensitive to their particular shape and thus is a general characteristic of the secondary CR ionization in dense gas.STAMPAenArticle10.3847/1538-4357/abdc272-s2.0-85103240284https://iopscience.iop.org/article/10.3847/1538-4357/abdc27https://api.elsevier.com/content/abstract/scopus_id/851032402842021ApJ...909..107IFIS/05 - ASTRONOMIA E ASTROFISICA