Astrophysics Seminar

Cosmic-ray (CR) transport and its impact on galaxy evolution remain open questions across vastly different environments. In the interstellar medium (ISM), puzzling gamma-ray observations continue to challenge our understanding of CR propagation, while in the circumgalactic medium (CGM), limited observations make it difficult to constrain the role of CRs. The problem is further compounded by the enormous dynamic range involved: the relevant physical scales span over ten orders of magnitude, from AU-scale CR gyroradii to halo-scale processes extending hundreds of kiloparsecs.

In the first part of my talk, I will present results from a suite of idealized simulations that investigate how CRs influence the dynamics and thermodynamics of the multiphase CGM. By incorporating CR injection from both host and satellite galaxies, we find that CR pressure significantly alters the evolution of ram-pressure–stripped clouds--expanding their surface area, enhancing mixing-layer cooling, and sustaining larger reservoirs of cold gas.

In the second part, I will shift to smaller scales and discuss how observable emission produced by CR populations can be spatially offset from their acceleration sites. Such offsets offer a powerful diagnostic of microphysical CR transport processes, particularly pitch-angle scattering, and provide a promising pathway to constrain CR transport.