Modeling Dust Production, Growth, and Destruction in Reionization-Era Galaxies with the CROC Simulations: Methods and Parameter Exploration

We introduce a model for the explicit evolution of interstellar dust in a cosmological galaxy formation simulation. We post-process a simulation from the Cosmic Reionization on Computers project (CROC, Gnedin 2014), integrating an ordinary differential equation for the evolution of the dust-to-gas ratio along pathlines in the simulation sampled with a tracer particle technique. This model incorporates the effects of dust grain production in asymptotic giant branch (AGB) star winds and supernovae (SN), grain growth due to the accretion of heavy elements from the gas phase of the interstellar medium (ISM), and grain destruction due to thermal sputtering in the high temperature gas of supernova remnants (SNRs). A main conclusion of our analysis is the importance of a carefully chosen dust destruction model, for which different reasonable parameterizations can predict very different values at the $\sim 100$ pc resolution of the ISM in our simulations. We run this dust model on the single most massive galaxy in a 10$h^{-1}$ co-moving Mpc box, which attains a stellar mass of $\sim 2\times10^9 M_{\odot}$ by $z=5$. We find that the model is capable of reproducing dust masses and dust-sensitive observable quantities broadly consistent with existing data from high-redshift galaxies. The total dust mass in the simulated galaxy is somewhat sensitive to parameter choices for the dust model, especially the timescale for grain growth due to accretion in the ISM. Consequently, observable quantities that can constrain galaxy dust masses at these epochs are potentially useful for placing constraints on dust physics.
Comment: Submitted to ApJ, comments welcome!