Supernova, Cosmic Rays, and Turbulence: Stars shaping interstellar gas

Cosmic Rays — Stars form within dense molecular gas, where cosmic rays (CRs) regulate ionization, chemistry, and magnetic coupling. Yet measuring the CR ionization rate (ζ) in these environments has remained a persistent challenge. I will present recent JWST observations of the starless core Barnard 68, revealing the first direct detection of CR-excited H₂ emission—a long-predicted but previously undetected signature. This allows a direct measurement of ζ, establishing molecular clouds as vast, naturally occurring CR detectors floating in space.

Supernovae — In the second part of the talk, I will shift gears to the large-scale structure of the ISM, highlighting how  3D dust maps uncover hidden features such as the recently identified “PerTau shell.” I will discuss the implications of such expanding shells for ISM dynamics and their potential role in driving turbulence and accelerating CRs.