The dependence of cooling and heating functions on local radiation fields
Date:
Abstract: Cooling and heating functions determine the thermal pressure support of gas clouds and the energy budget of gas. These functions are a key component in how gas clouds collapse to form stars and subsequently galaxies. The radiative transfer physics underlying cooling and heating functions is known but is too computationally expensive to include in hydrodynamic simulations for realistic local radiation fields within galactic halos. Hence, a fast approximation to the dependence on the incident radiation field is needed to include local effects. We first discuss results from an existing approximation to heating and cooling functions in a simulation from the Cosmic Reionization on Computers project. We find that the simulated gas thermodynamics cannot be adequately described by functions computed with a spatially constant radiation field. We also discuss ongoing work using machine learning to investigate what wavelength bands of the radiation field most strongly affect cooling and heating functions.