Dust in High-Redshift Galaxies: Reconciling UV Attenuation and IR Emission

Understand

Dust is a key component of galaxies, but its properties during the earliest eras of structure formation remain elusive.

• Here we present a simple semi-analytic model of the dust distribution in galaxies at $z \gtrsim 5$.
• We calibrate the free parameters of this model to estimates of the UV attenuation (using the IRX-$\beta$ relation between infrared emission and the UV spectral slope) and to ALMA measurements of dust emission.
• We find that the observed dust emission requires that most of the dust expected in these galaxies is retained (assuming a similar yield to lower-redshift sources), but if the dust is spherically distributed, the modest attenuation requires that it be significantly more extended than the stars.