Scrutinising several hundred thousand galaxies observed at infrared and submillimetre wavelengths by ESA’s Herschel space observatory, astronomers have identified a very rare instance of a massive object in the very early Universe.
This video initially shows the Herschel survey of galaxies (blue and green) and zooms in to the interesting source that the astronomers had singled out, including follow-up observations performed with the Atacama Pathfinder Experiment (APEX; red).
Finally, the video shows further observations obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) at higher resolution. These observations revealed that the source consists not just of one ancient, massive galaxy, but of a pair of distinct massive galaxies about to merge.
These two galaxies, each roughly as massive as our Milky Way, were informally dubbed the ‘Horse’ and the ‘Dragon’.

Full story: Herschel discovers galaxy merger in the very early Universe