Simulating the ISM and its Line Emission

Integral field observations of galaxies now produce spatially resolved emission line diagnostic diagrams that can reveal the diverse processes impacting the ISM, and are necessarily dependent on the geometry and distribution of their gas clouds. Simulations of galaxies can now model the diverse geometries of interstellar clouds, which are often different than the simple geometries employed in photoionisation codes like cloudy. Thus, we suggest that the future of emission line modeling will necessarily require combining photoionisation models with full hydrodynamical simulations of galaxies, ideally including radiative transfer as well. I will present an overview of the interstellar clouds produced in the NUT and NEPHTHYS galaxies, formed in high-redshift, zoom cosmological simulations of up to 10 pc resolution. I will then present our methods to characterise feedback as it impacts these clouds, and predict the resulting emission lines. Finally, emission line model tools also play a role in predicting the abundance of ions in the circumgalactic medium (CGM), which are observed in absorption in observations of background quasars. Thus, we suggest future development of line emission models keep the CGM in mind, as galactic processes that impact the ISM also impact the CGM. Taken together observations of the ISM and CGM can be more constraining for these models