Abstract

Invited Talk - Plenary

Thursday, 10 September 2026, 11:30   (MW-1801 / virtual plenum)

Towards next-generation cosmic-ray astrochemistry models

Brandt Gaches
University of Duisburg-Essen

In dense molecular gas, shielded from ultraviolet radiation, energetic, charged particles, dubbed cosmic rays, are the dominant source of ionization. Cosmic-ray ionization drives a diverse gas-phase chemistry, and their interactions with icy dust grains stimulate complex organic and prebiotic chemistry in their ice. The cosmic-ray ionization rate is thus a fundamental parameter in astrochemical models. Despite their importance, cosmic rays are often treated very simply. However, new observations also show that particles may be accelerated within clouds during star formation and that there are ionization gradients. I will introduce possible embedded sources of particle acceleration in molecular clouds and their potential impact on astrochemical models. I will also highlight novel three-dimensional astrochemical models that include a range of cosmic ray processes, including cosmic ray attenuation and direct excitation of molecular hydrogen. Finally, I will highlight current on-going works within my group to provide new state-of-the-art three-dimensional chemical models that will help significantly improve our understanding of the impact of cosmic rays on dense molecular gas.