Nuclear de-excitation lines as a probe of low-energy cosmic rays

TL;DR

This paper investigates how nuclear de-excitation lines can be used to probe low-energy cosmic rays, providing insights into their interactions, origins, and effects on the interstellar medium.

Contribution

It combines numerical nuclear reaction modeling with cosmic ray propagation to analyze de-excitation lines as a diagnostic tool for LECRs.

Findings

De-excitation lines carry unique information about LECRs.

LECRs are concentrated near their acceleration sites due to slow propagation.

The study presents a new combined modeling approach for nuclear reactions and cosmic ray propagation.

Abstract

Low-energy cosmic rays (LECRs) contribute substantially to the energy balance of the interstellar medium. They play also significant role in the heating and chemistry of gas, and, consequently, on the star formation process. Because of the slow propagation coupled with enhanced energy losses of subrelativistic particles, LECRs are concentrated around their acceleration sites. LECRs effectively interact with the ambient gas through nuclear reactions. Although these processes are energetically less effective compared to heating and ionization, they are extremely important from the point of view of nuclear de-excitation lines, which carry unique information about LECRs. We present results on production of de-excitation lines combining the numerical treatment of nuclear reactions using the code TALYS, with the propagation and energy losses of LECRs.