On the Stellar Populations of Galaxies at z=9-11: The Growth of Metals and Stellar Mass at Early Times

We present a detailed stellar population analysis of 11 bright (H < 26.6) galaxies at z = 9-11 (three spectroscopically confirmed) to constrain the chemical enrichment and growth of stellar mass of early galaxies. We use the flexible Bayesian spectral energy distribution (SED) fitting code Prospector with a range of star formation histories (SFHs), a flexible dust attenuation law, and a self-consistent model of emission lines. This approach allows us to assess how different priors affect our results and how well we can break degeneracies between dust attenuation, stellar ages, metallicity, and emission lines using data that probe only the rest-frame ultraviolet (UV) to optical wavelengths. We measure a median observed UV spectral slope beta=-1.87(-0.43)(+0.35) for relatively massive star-forming galaxies (9 10.

Automated summary

We conducted a detailed stellar population analysis of 11 bright galaxies at z = 9-11 and used a flexible Bayesian spectral energy distribution (SED) fitting code to study their chemical enrichment and growth of stellar mass. Our results show the impact of different priors on the analysis and how well we can break degeneracies between various parameters using only UV to optical wavelength data. The correlation between dust attenuation, stellar ages, metallicity, and emission lines was explored using this approach.