JWST Spots 70 Metal-Rich Early Galaxies
In collaboration with ALMA, JWST identified 70 dust-rich, metal-laden star-forming galaxies from less than a billion years after the Big Bang. The presence of so much dust and metal so early implies that galactic evolution and the cycle of star birth and death began much earlier than previously believed, potentially expanding the window for habitable planet formation.
- This joint investigation initially identified a population of 400 bright, dust-rich galaxies using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Follow-up observations with the James Webb Space Telescope (JWST) narrowed this down to 70 faint, dusty galaxy candidates. - In astronomy, "metals" are any elements heavier than hydrogen and helium. Finding them in such early galaxies challenges existing models because it was believed that it would take much longer for stars to create and distribute these heavier elements. - The galaxies are observed as they were less than a billion years after the Big Bang, with some confirmed to have formed as early as 500 million years after the Big Bang. - This research is part of a larger ALMA survey called the ALMA Large Program to Investigate C+ at Early Times (ALPINE). The survey targets 118 galaxies to study their gas and dust properties during a period of rapid growth. - The discovery of so much dust so early helps to bridge a gap between two other known populations of early galaxies: extremely bright, star-forming galaxies and older, "dead" galaxies that are no longer forming stars. - The presence of dust is crucial for the formation of stars and planets. The dust clouds absorb stellar light and eventually become the birthplaces for new celestial bodies. - Recent JWST discoveries in other early, metal-poor galaxies have revealed unexpected types of dust, such as grains made almost entirely of iron, challenging theories that supernovae were the sole producers of dust in the early universe. - Other JWST programs, like the Advanced Deep Extragalactic Survey (JADES), have also detected the chemical signatures of carbon-rich dust grains in the first billion years of the universe, suggesting infant galaxies developed much faster than previously anticipated.
