Abstract

Although rare in the nearby Universe, gas-rich galaxies with extraordinary star-formation rates (100-1000x the Milky Way, at >100 Msun/year) represent the typical massive galaxy in the early Universe 10 billion years ago. These galaxies’ high star-formation rates are predominantly obscured by dust which absorbs and re-radiates >95% of the energy from massive stars in the (sub)millimeter/far-infrared, hence they are often called dusty star-forming galaxies (DSFGs). Thanks to facilities like the Herschel Space Observatory in the early 2010s, we have successfully mapped the contribution of such DSF Gs to cosmic star-formation from z=0 back to z=2, where it appears they are factors of 1000x more common than they are locally and, indeed, dominate. I will discuss current efforts underway with ALMA to take an unbiased census of completely obscured galaxies from z=2 towards the Epoch of Reionization. The detection of incredibly dust-rich systems (>10^9 Msun of dust) at these early epochs are key to understanding both the early formation mechanisms of dust (from supernovae, AGB stars and via grain growth in the ISM ) and the assembly history of the Universe’s most massive galaxies and their rich, over dense environments.