Modeling Dust Production, Growth, and Destruction in Reionization-Era Galaxies with the CROC Simulations II: Predicting the Dust Content of High-Redshift Galaxies

TL;DR

This study uses cosmological simulations to model dust in early galaxies, testing how dust physics affect observable properties, but finds current models struggle to match all observational constraints, highlighting the importance of stellar feedback.

Contribution

It introduces a post-processing method to vary dust creation and destruction parameters in simulations of high-redshift galaxies, assessing their impact on observable properties.

Findings

Models with high dust production yield too much UV extinction.

Simulated dust and star distributions are overly symmetric compared to observations.

Current stellar feedback models may limit accurate dust distribution predictions.

Abstract

We model the interstellar dust content of the reionization era with a suite of cosmological, fluid-dynamical simulations of galaxies with stellar masses ranging from $\sim 10^5 - 10^9 M_{\odot}$ in the first $1.2$ billion years of the universe. We use a post-processing method that accounts for dust creation and destruction processes, allowing us to systematically vary the parameters of these processes to test whether dust-dependent observable quantities of galaxies at these epochs could be useful for placing constraints on dust physics. We then forward model observable properties of these galaxies to compare to existing data. We find that we are unable to simultaneously match existing observational constraints with any one set of model parameters. Specifically, the models which predict the largest dust masses $D/Z \gtrsim 0.1$ at $z = 5$ -- because of high assumed production yields and/or efficient growth via accretion in the interstellar medium -- are preferred by constraints on total dust mass and infrared luminosities, but these models produce far too much extinction in the ultraviolet, preventing them from matching observations of $\beta_{\rm UV}$. To investigate this discrepancy, we analyze the relative spatial distribution of stars and dust as probed by infrared (IR) and ultraviolet (UV) emission, which appear to exhibit overly symmetric morphologies compared to existing data, likely due to the limitations of the stellar feedback model used in the simulations. Our results indicate that the observable properties of the dust distribution in high redshift galaxies are a particularly strong test of stellar feedback.