Astronomy & Astrophysics Seminar: How Do Stars Shape Interstellar Gas? Cosmic Rays, UV Radiation, and Turbulence

Zoom: https://tau-ac-il.zoom.us/j/87185167411?pwd=FpTUyIgXaOturzOFSetA6pPVYQilen.1

Abstract:

Cosmic rays play a central role in the interstellar medium, especially in the cold dense clouds where stars form. There they control the ionization, chemistry, thermal balance, and magnetic coupling of the gas, yet their low-energy population remains notoriously difficult to measure. In this talk I will present recent progress in directly tracing cosmic rays in molecular gas, focusing on our JWST detection of cosmic-ray-excited H_2 emission from the starless core Barnard 68. This provides a new and direct way to measure the cosmic-ray ionization rate, opening the possibility of using molecular clouds as giant detectors of low-energy cosmic rays.

I will also briefly discuss ongoing work on the thermal phases of the local interstellar medium, including a new three-dimensional map of its thermal structure, and what it implies about the role of turbulence in sustaining thermally unstable gas. These studies connect small-scale cloud physics to the broader problem of how cosmic rays, turbulence, and thermal processes regulate star formation and galaxy evolution.

Seminar Organizer: Dr. Jonathan Stern

Recording >