On the missing dust of super-early galaxies: Supernova blowout and gas-dust venting in Blue Monsters

TL;DR

This paper investigates how supernova-driven blowout and gas-dust venting in early galaxies can explain their unexpectedly low dust content, aligning with observations of Blue Monsters at high redshift.

Contribution

It introduces a model combining hydrodynamical simulations and thin-shell scalings to quantify dust loss due to supernova-driven venting in early galaxies.

Findings

Mechanical venting reduces dust-to-stellar mass ratio by up to two orders of magnitude.

The model explains low dust fractions in Blue Monsters without extreme destruction or fine-tuning.

Dust retention depends mainly on gas concentration, weakly on metallicity.

Abstract

A subset of very young, super-early galaxies at $z\gtrsim10$, often termed Blue Monsters, shows extremely blue UV continua and faint far-IR emission, which could imply much less dust than expected from standard enrichment scenarios. We seek to understand the possible reason behind the apparent absence of dust in the Blue Monsters. We show how clustered supernovae drive mechanical blowout in stratified, self-gravitating clouds by combining full 3-D hydrodynamical dust-survival yields with 3-D thin-shell scalings, and we predict the retained dust-to-stellar mass ratio at the cluster scale and the corresponding galaxy-integrated value. We take the net dust yield per unit stellar mass from existing 3-D hydrodynamical studies of young stellar clusters with sequential supernovae, and we set the blowout radius as a function of gas concentration using established 3-D thin-shell scalings. Assuming gas-dust coupling across the blowout boundary, the retained dust-to-stellar ratio accounts for the fraction of supernovae that remain confined versus those that vent mechanically. Across typical cluster masses, sizes, and cloud-scale star formation efficiencies, mechanical venting removes a large share of gas and dust. The retained dust-to-stellar mass ratio is lowered by about half to two orders of magnitude relative to the supernova net dust yield. The outcome depends mainly on gas concentration and only weakly on metallicity, so it remains effective at low $Z$. After weighting by a Schechter cluster mass function and a Weibull core-radius distribution, the galaxy-integrated value falls in the same range inferred for spectroscopically confirmed Blue Monsters. Thus, mechanical venting at the cluster scale can account for the very low dust fractions inferred for Blue Monsters without requiring extreme in situ destruction and without fine-tuning.