A New Model For Including Galactic Winds in Simulations of Galaxy Formation I: Introducing the Physically Evolved Winds (PhEW) Model

TL;DR

The paper introduces the Physically Evolved Winds (PhEW) model, an analytic approach to simulate cold galactic winds more accurately in galaxy formation models by incorporating physical processes like conduction and instabilities.

Contribution

It presents a novel sub-grid model for galactic winds that aligns with high-resolution simulations, improving the physical realism of galaxy formation simulations.

Findings

Model reproduces high-resolution cloud-crushing simulation results.

Incorporates thermal conduction and hydrodynamic instabilities.

Provides a robust sub-grid prescription for cosmological simulations.

Abstract

The propagation and evolution of cold galactic winds in galactic haloes is crucial to galaxy formation models. However, modelling of this process in hydrodynamic simulations of galaxy formation is over-simplified owing to a lack of numerical resolution and often neglects critical physical processes such as hydrodynamic instabilities and thermal conduction. We propose an analytic model, Physically Evolved Winds (PhEW), that calculates the evolution of individual clouds moving supersonically through a uniform ambient medium. Our model reproduces predictions from very high resolution cloud-crushing simulations that include isotropic thermal conduction over a wide range of physical conditions. We discuss the implementation of this model into cosmological hydrodynamic simulations of galaxy formation as a sub-grid prescription to model galactic winds more robustly both physically and numerically.