The structure of HI in galactic disks: Simulations vs observations

TL;DR

This paper compares simulated and observed galactic HI structures, demonstrating that including stellar feedback in simulations produces more realistic HI scale heights, structures, and self-absorption features consistent with observations.

Contribution

It introduces a simulation approach with stellar feedback that better replicates observed galactic HI properties, including scale height and self-absorption morphology.

Findings

Increased HI scale height with feedback matches observations

Simulated HI structures include supernova bubbles similar to real galaxies

HI self-absorption properties are consistent with observational data

Abstract

We generate synthetic HI Galactic plane surveys from spiral galaxy simulations which include stellar feedback processes. Compared to a model without feedback we find an increased scale height of HI emission (in better agreement with observations) and more realistic spatial structure (including supernova blown bubbles). The synthetic data show HI self-absorption with a morphology similar to that seen in observations. The density and temperature of the material responsible for HI self-absorption is consistent with observationally determined values, and is found to be only weakly dependent on absorption strength and star formation efficiency.