2026/07/21 by Sergio Martínez-González, Casiana Muñoz-Tuñón, Santiago Jiménez
#astro-ph.GA #astro-ph.CO
JWST has revealed galaxies at z>10 with extremely blue UV-continuum slopes approaching β\rm UV\lesssim-2.4, and low inferred dust contents. At similar redshifts, JWST and ALMA reveal dusty massive systems reaching β\rm UV\gtrsim-1. We aim to explain blue monsters and red monsters at z\gtrsim10 as different outcomes of supernova dust retention in clustered star-forming systems and connect this bimodality to dusty massive galaxies at z≃6--7. We model dust removal in a cluster-dominated regime through cloud-scale mechanical blowout followed by breakout from stratified high-redshift disks. The shock-processed dust mass retained in the UV-attenuating layer is converted into a UV-continuum slope using absorption opacities derived from 3D hydrodynamical simulations of clustered supernovae in porous molecular clouds. In compact, gas-rich galaxies, efficient cloud blowout and disk breakout reduce the retained dust fraction to blue-monster levels, yielding β\rm UV\lesssim-2.4. Larger stellar masses increase the retained dust column and produce red-monster-like systems with β\rm UV\gtrsim-1.5, reaching β\rm UV≃-0.5 when radiative losses weaken large-scale driving. The transition depends on whether clustered-supernova ejecta cross both the natal cloud and the galactic gas layer. Supernova dust production, shock processing, radiative losses, and mechanical venting can jointly explain UV-bright dust-poor galaxies and red dusty massive systems across 6\lesssim z\lesssim14.