Figure 1. A simulated 277-GHz continuum map with the 6-m ACT telescope (left) and AtLAST (right) without instrument noise.

The ACT map is limited by confusion noise at X mJy level (notice the seemingly overlapping faint sources); thanks to its 50-m dish, AtLAST will be able to resolve much fainter (up to four orders of magnitude) individual sources. These mock images are based on simulated galaxy catalogues from Lagos et al. (2020).