Artist’s illustration of the observed field. In each close-up view, left is the illustration of the optical (blue) and conventional millimeter/submillimeter (red) image and right is the optical and ALMA image.
Existing millimeter/submillimeter telescopes could not identify the sources of the emission due to their low resolution, however, ALMA pinpoints the galaxies which emit the emission. These objects were not detected in the optical observations, which indicate that they are heavily embedded in dust.
Image Credit: ALMA (ESO/NAOJ/NRAO) / Kyoto University