Abstract

Contributed Talk - Splinter CompQuantum   (MW-2050)

A turbulent story of cooling and mixing in the circumgalactic medium

Alankar Dutta
Max Planck Institute for Astrophysics

Multiphase gas surrounding galaxies - the circumgalactic medium (CGM) - plays a crucial role in shaping the kinematic and thermodynamic state of a galaxy. This environment hosts ionized, neutral, and molecular gas, and is closely linked to the formation and evolution of its host galaxy: star formation, for instance, is regulated by the circulation and feedback of gas and metals to and from the galactic disk, mediated by the multiphase CGM. Understanding and modelling this multiphase gas - which spans several orders of magnitude in temperature, density, and spatial scale - remains a central challenge in galaxy formation research. In this talk, I present our past and ongoing work on several complementary approaches to understanding the physics of the turbulent, multiphase CGM. I will first show how phenomenological modelling captures the structure of cold and clumpy clouds in the CGM, and how such models can be constrained using synthetic observations. I will then discuss how small-scale (pc to a few kpc) idealized simulations of turbulent, multiphase gas build a coherent understanding of turbulent mixing and radiative cooling in the CGM - refining, and in turn constraining, the inferences drawn from phenomenological modelling. I will further highlight how these idealized simulations shed light on diffusive processes such as thermal conductivity and viscosity in the CGM. Together, these simulations serve as a stepping stone toward an effective sub-grid model of multiphase gas for large-scale cosmological simulations, where self-consistently resolving the impact of such small-scale physics remains an outstanding challenge.