The Impact of Cosmic Rays on Star Formation
Margot Fitz Axen, University of Texas at Austin
Cosmic rays (CRs) are one of the primary constituents of the ISM and are the main driver of ionization in star-forming molecular clouds. They are accelerated by high-energy shocks from sources external to the clouds such as supernova remnants and by the shocks at the collapsing protostars inside the cloud. Despite their impact on gas temperature, kinematics, and chemistry, they have not been included in previous simulations of star formation. We run simulations of a collapsing turbulent molecular cloud with the GIZMO code that includes explicitly modeling CR transport from galactic CRs. We assess the impact of CRs on star formation and post-process the simulations to compute their effect on observational diagnostics. We find that in environments where the CR background is comparable to that of the Milky Way, the effect of including CR transport on the star formation in the cloud is minimal. However, in high CR environments such as near CR acceleration sources, CRs have a significant impact on the gas dynamics and increase the star formation in the cloud.
Abstract Author(s): Margot Fitz Axen, Stella Offner