"The Alma Chemical Evolution (ACE) Large Program: Cold Dust in Metal-Poor Galaxies at Cosmic Noon"

Abstract

Dust plays a key role in galaxy evolution by influencing star formation and shaping the observed spectrum of galaxies. The total amount of dust in a galaxy depends on the abundance of metals in the interstellar medium, since metals regulate the processes of production, growth, and destruction of dust. However, at z~2 (Cosmic Noon) our knowledge of the dust mass budget is limited to the most massive, metal-rich systems, which are not representative of the bulk galaxy population. The ALMA Chemical Evolution (ACE) Large Program aims to extend this knowledge into the sub-solar gas-phase metallicity regime with a sample of 25 main-sequence galaxies at z~2.3. In this talk, I present dust mass measurements for the ACE sample based on deep ALMA continuum observations. Thanks to an exquisite ancillary dataset from Keck, HST, and JWST, I study the dust content as a function of stellar mass, star formation rate (SFR), and metallicity, among others. The resulting dust masses are clearly in excess with respect to z=0 samples at a matched metallicity and stellar mass, as expected by the higher gas fractions observed at z=2, yet the dust mass per unit SFR is slightly lower than at z=0. Overall, I find only mild trends with metallicity down to 1/3 solar, but a clear correlation with both stellar mass and SFR, in broad agreement with semi-analytical models and hydrodynamical simulations. Finally I compare these results to recent observations at higher redshifts and discuss the implications for dust evolution across cosmic time.