Tuesday, January 5, 2021
Our current understanding of star formation and galaxy evolution within the first two billion years of the Big Bang is severely biased toward unobscured star formation tracers and thus limited due to sample incompleteness. Detecting dusty star-forming galaxies (DSFGs) at high redshifts require observations at far-infrared, submillimeter, and millimeter wavelengths, which trace the dust re-processed UV/optical emission from young stars. Within the last year, massive, but optically-invisible DSFGs (called HST-dark as they have gone undetected in the deepest Hubble Space Telescope images) have been discovered by the Atacama Large Millimeter/submillimeter Array (ALMA) posing new questions for the field such as: 1) How ubiquitous are HST-dark DSFGs in the early Universe? and 2) What do the evolutionary tracks of these HST-dark DSFGs look like; for example, do they evolve into the massive quiescent galaxies which have recently been discovered out to z=4? In this talk I will discuss efforts to characterize DSFGs across two redshift regimes (1<z<3 and z>4), the multiwavelength characterization of two HST-dark sources found in the recent MORA survey, and the implications this newfound population may have on our understanding of galaxy evolution in the early Universe.