Researchers using the radio telescope ALMA (Atacama Large Millimeter/submillimeter Array) observed signals of oxygen, carbon, and dust from a galaxy in the early Universe 13 billion years ago.
Researchers determined that the galaxy is actually two galaxies merging together making it the earliest example of merging galaxies yet discovered.
ALMA detected radio emissions from oxygen, carbon, and dust in B14-65666.T he detection of multiple signals is important because they carry complementary information.
Data analysis showed that the emissions are divided into two blobs. Previous observations with the radio telescopeHubble Space Telescope (HST) had revealed two star clusters in B14-65666. Now with the three emission signals detected by ALMA, the team was able to show that the two blobs do in-fact form a single system, but they have different speeds.
This indicates that the blobs are two galaxies in the process of merging. This is the earliest known example of merging galaxies. The research team estimated that the total stellar mass of B14-65666 is less than 10% that of the Milky Way.
This means that B14-65666 is in the earliest phases of its evolution. Despite its youth, B14-65666 is producing stars 100 times more actively than the Milky Way. Such active star-formation is another important signature of galactic mergers, because the gas compression in colliding galaxies naturally leads to bursty star-formation.
Modern galaxies like our Milky Way have experienced countless, often violent, mergers. Sometimes a larger galaxy swallowed a smaller one. In rare cases, galaxies with similar sizes merged to form a new, larger galaxy.