massive galaxy formation tagged posts

The Aurora Australis, or Southern Lights, over the South Pole Telescope at NSF’s Amundsen-Scott South Pole Station. Credit: Dr. Keith Vanderlinde, NSF

Observations of two galaxies made with ALMA radio telescope suggest that large galaxies formed faster than scientists had previously thought. The two galaxies, first discovered by the South Pole Telescope at NSF’s Amundsen-Scott South Pole Station in Antarctica, were massive and star-filled at a time when the cosmos was < 1B years old. The observation came as a surprise, considering astronomers had thought that the first galaxies, which formed just a few hundred million years after the Big Bang, were similar to today’s dwarf galaxies – collections of stars much smaller than the Milky Way...

Artist impression of a pair of galaxies from the very early universe. Credit: NRAO/AUI/NSF; D. Berry

New observations push back the epoch of massive-galaxy formation even further by identifying two giant galaxies seen when the universe was only 780 million years old, or about 5% its current age. Astronomers expect that the first galaxies, those that formed just a few hundred million years after the Big Bang, would share many similarities with some of the dwarf galaxies we see in the nearby universe today. These early agglomerations of a few billion stars would then become the building blocks of the larger galaxies that came to dominate the universe after the first few billion years.

Ongoing observations with ALMA however, have discovered surprising examples of massive, star-filled galaxies...