AR 14299 (Archival Research)

Sun Jul 14 04:25:27 GMT 2024

Principal Investigator: Neal Katz
PI Institution: University of Massachusetts - Amherst
Investigators (xml)

Title: A New Galactic Wind Model to Better Understand the Implications of QSO Absorption lines
Cycle: 23

QSO absorption line studies of the CGM using HST COS are the best direct way to study the accretion and galactic wind processes that are thought to dominate galaxy formation. Detailed numerical simulations are critical to interpret and understand these observations. Unfortunately, interactions at wind/halo gas interfaces in the CGM occur on scales that are much below the resolution of any current galaxy formation simulation. To mitigate this impasse, we propose to implement a new wind algorithm that explicitly models the "subgrid physics" in the wind-halo gas interaction analytically within a simulation, using the simulation to provide the physical characteristics that will inform the interaction. Unavoidably, this introduces a couple free parameters but we can restrict them by matching observed galaxy properties. We will conduct simulations to test and tune the new wind model to match the galaxy stellar and HI mass function. Then using the new wind model, we will perform a large-volume, high-resolution simulation that we will compare with COS observations similar to our group's previous comparisons, to better understand their implications for galaxy formation. Our existing simulations reproduce many observed properties of galaxies and metal-line absorption, but the new wind implementation will allow us to tie empirical successes, and failures, more securely to the underlying wind physics, both the ejection (mass-loading factors and ejection speeds) and the interaction between the wind and gaseous halo, and allow us to identify absorption line features with specific physical processes. We will publicly release the wind model and artificial spectra from the simulation.