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