Dust extinction in the first galaxies

Using cosmological volume simulations and a custom built sub-grid model for Population III (Pop III) star formation, we examine the baseline dust extinction in the first galaxies due to Pop III metal enrichment in the first billion years of cosmic history. We find that although the most enriched, high-density lines of sight in primordial galaxies can experience a measurable amount of extinction from Pop III dust [E(B - V)(max) = 0.07, A(v,max) approximate to 0.28], the average extinction is very low with (E(B - V)) less than or similar to 10(-3). We derive a power-law relationship between dark matter halo mass and extinction of E(B - V) alpha M-halo(0.80) Performing a Monte Carlo parameter study, we establish the baseline reddening of the ultraviolet spectra of dwarf galaxies at high redshift due to Pop III enrichment only. With this method, we find (beta(uv)) - 2.51 +/- 0.07, which is both nearly halo mass and redshift independent.