The problematic growth of dust in high redshift galaxies

Understand

Dust growth via accretion of gas species has been proposed as the dominant process to increase the amount of dust in galaxies.

• We show here that this hypothesis encounters severe difficulties that make it unfit to explain the observed UV and IR properties of such systems, particularly at high redshifts.
• Dust growth in the diffuse ISM phases is hampered by (a) too slow accretion rates; (b) too high dust temperatures, and (c) the Coulomb barrier that effectively blocks accretion.
• In molecular clouds these problems are largely alleviated.