Limits on Intergalactic Dust During Reionization

TL;DR

This paper constrains the amount of dust in the intergalactic medium during the epoch of reionization, showing it was less than 3% of the Milky Way's dust-to-gas ratio by redshift 10.

Contribution

It provides the first constraints on the intergalactic dust-to-gas ratio at high redshifts using models and observations of galaxy reddening.

Findings

IGM was enriched to less than 3% of Milky Way dust-to-gas ratio by z=10

High-redshift galaxy reddening limits intergalactic dust content

Dust levels during reionization are very low, impacting galaxy formation models

Abstract

In this Letter, we constrain the dust-to-gas ratio in the intergalactic medium (IGM) at high redshifts. We employ models for dust in the local Universe to contrain the dust-to-gas ratio during the epoch of reionization at redshifts z ~ 6-10. The observed level of reddening of high redshift galaxies implies that the IGM was enriched to an intergalactic dust-to-gas ratio of less than 3% of the Milky Way value by a redshift of z=10.