DUSTiER (DUST in the Epoch of Reionization): dusty galaxies in cosmological radiation-hydrodynamical simulations of the Epoch of Reionization with RAMSES-CUDATON

Abstract

In recent years, interstellar dust has become a crucial topic in the study of the high and very high redshift Universe. Evidence points to the existence of high dust masses in massive star forming galaxies already during the Epoch of Reionization, potentially affecting the escape of ionising photons into the intergalactic medium. Moreover, correctly estimating dust extinction at UV wavelengths is essential for precise ultra-violet luminosity function (UVLF) prediction and interpretation. In this paper, we investigate the impact of dust on the observed properties of high redshift galaxies, and cosmic reionization. To this end, we couple a physical model for dust production to the fully coupled radiation-hydrodynamics cosmological simulation code RAMSES-CUDATON, and perform a 16 cMpc 3 h −3 , 2048 3 , simulation, that we call DUSTiER for DUST in the Epoch of Reionization. It yields galaxies with dust masses and UV slopes compatible with constraints at z ≥ 5. We find that extinction has a dramatic impact on the bright end of the UVLF, even as early as z = 8, and our dusty UVLFs are in better agreement with observations than dust-less UVLFs. The fraction of obscured star formation rises up to 55% at z = 5, in agreement with some of the latest results from ALMA. Finally, we find that dust reduces the escape of ionising photons from galaxies more massive than 10 10 M (brighter than ≈ -18 M AB1600 ) by >10%, and possibly up to 80-90% for our most massive galaxies. Nevertheless, we find that the ionising escape fraction is first and foremost set by neutral Hydrogen in galaxies, as the latter produces transmissions up to 100 times smaller than through dust alone.

Co-evolution of Dust and Chemistry in Galaxy Simulations with a Resolved Interstellar Medium

“…Cosmological simulations and isolated galaxy simulations with comparable resolution have started to include dust evolution models at different levels of sophistication (McKinnon et al 2017(McKinnon et al , 2018Aoyama et al 2017Aoyama et al , 2018Li et al 2019;Parente et al 2022;Lewis et al 2022;Romano et al 2022;Lower et al 2022). However, these simulations do not resolve either SN feedback or the density structure of the ISM, forcing them to adopt dust evolution models in a sub-grid fashion.…”