Speaker
Dr
Giovanni Morlino
(Gran Sasso Science Institute)
Description
Cosmic rays (CR) are a fundamental source of ionization for molecular clouds as well as diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of CR inside a cloud also determines the γ-ray flux produced by hadronic collisions between CR and cloud materials. We study the spectrum of CR inside and outside a diffuse cloud for energies > MeV. We solve the stationary transport equation for CR in 1-D including diffusion, advection and losses due to ionization of neutral Hydrogen atoms. We found that, for typical number density of diffuse clouds $\sim 100$ cm$^{−3}$, and cloud size of $\sim 10$ pc, the CR spectrum just on the edge of the cloud has a break at energy $E_{br}$ ∼ 100 MeV. This breaking energy is due to the fact that particles can cross the cloud many times, hence increasing the energy losses. The presence of the breaks also depends on the CR spectrum far from the cloud.
| Registration number following "ICRC2015-I/" | 1148 |
|---|---|
| Collaboration | -- not specified -- |
Author
Dr
Giovanni Morlino
(Gran Sasso Science Institute)
Co-author
Dr
Stefano Gabici
(CNRS/IN2P3, APC, Université Paris Diderot)
