Cosmic Reionization On Computers. Ultraviolet Continuum Slopes and Dust Opacities in High Redshift Galaxies

TL;DR

This paper compares simulated high-redshift galaxy properties with observational data, highlighting the need for more detailed dust modeling to match future high-precision JWST observations.

Contribution

It introduces a method to incorporate dust into galaxy simulations using dust-follows-metals ansatzes and assesses their accuracy against real data.

Findings

Simulation results generally match observational data

Discrepancies suggest current dust modeling is insufficient

Future JWST data will require more detailed dust evolution models

Abstract

We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are not fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.