Hydrodynamic Simulations and Time-dependent Photoionization Modeling of Starburst-driven Superwinds

TL;DR

This paper combines hydrodynamic simulations with time-dependent photoionization models to better understand the complex thermal and ionization structures of starburst-driven superwinds, moving beyond simple adiabatic assumptions.

Contribution

It introduces a coupled hydrodynamic and non-equilibrium photoionization modeling approach to study superwinds, providing more accurate predictions of their physical and ionization structures.

Findings

Time-dependent ionization states reveal complex superwind structures.

Simulations show non-equilibrium effects significantly influence emission lines.

Results suggest radiative cooling impacts superwind evolution.

Abstract

Thermal energies deposited by OB stellar clusters in starburst galaxies lead to the formation of galactic superwinds. Multi-wavelength observations of starburst-driven superwinds pointed at complex thermal and ionization structures which cannot adequately be explained by simple adiabatic assumptions. In this study, we perform hydrodynamic simulations of a fluid model coupled to radiative cooling functions, and generate time-dependent non-equilibrium photoionization models to predict physical conditions and ionization structures of superwinds using the MAIHEM atomic and cooling package built on the program FLASH. Time-dependent ionization states and physical conditions produced by our simulations are used to calculate the emission lines of superwinds for various parameters, which allow us to explore implications of non-equilibrium ionization for starburst regions with potential radiative cooling.