Evrim Yazgin
Cosmos science journalist
Astronomers have spotted massive red galaxies dating back to the first billion years of the universe’s life. Some are almost as large as the Milky Way.
This suggests stars and galaxies grew more quickly in the early universe than previously thought.
The discovery was made using data from the James Webb Space Telescope (JWST) and is detailed in a paper published in Nature. It follows other JWST discoveries of large galaxies forming within the first several hundred million years of the universe.
“The question of ‘impossibly’ massive galaxies shortly after the Big Bang has vexed astronomers since the first images of the James Webb Space Telescope,” says co-author Ivo Labbé, an associate professor at Melbourne’s Swinburne University of Technology.
“This is akin to finding a toddler weighing 100kg. JWST has now proven monsters do roam the early universe.”
Current models of galaxy formation suggest they form gradually in large halos of dark matter. Only about 20% of the matter captured by the gravity of the dark matter would have formed stars.
The research used data from JWST’s FRESCO survey. 36 massive galaxies were analysed in the study. The galaxies are called “red monsters” because they have a distinctive red glow in the JWST images due to their high dust content. Most galaxies observed by the team fit the current explanation for galaxy formation in the early universe.
But 3 massive galaxies in the early universe are forming stars nearly twice as fast.
“Current models fail to explain how it is possible star formation is so super-efficient, very early in the universe,” Labbé adds. “The usual assumption is that exploding stars and supermassive black holes kill star formation, blowing out the candle. No doubt future Webb observations will provide us clues as to what we are missing.”
