| Recent simulations have suggested that the CGM around low-redshift L* galaxies may be primarily supported by cosmic-ray pressure, marking a significant departure from the traditionally understood thermal-pressure-supported CGM. Yet, the task of validating or refuting these theories has proven remarkably challenging. Theoretically, the accuracy of these predictions hinges on the specifics of cosmic-ray transport models, which remain largely unconstrained. Observationally, directly constraining the cosmic-ray energy within the CGM is out of reach for today’s telescopes. Making progress, therefore, will require a multifaceted approach. In this talk, I will first describe the predicted characteristics of a cosmic-ray-pressure-supported CGM. Following this, I will explore several avenues for progress, including theoretical and observational efforts to refine cosmic-ray transport models, observational strategies to better delineate the physical structure of the CGM, and the potential of leveraging subgrid models to simulate CGM microphysics at the resolution of current galaxy simulations. |
