Astronomers using the NASA/ESA/CSA James Webb Space Telescope have discovered three ultra-massive galaxies — nearly as massive as our own Milky Way Galaxy — already in place within the first billion years after the Big Bang. Part of the JWST/FRESCO survey, this discovery indicates that stars in the early Universe grew much more rapidly than previously thought, challenging existing galaxy formation models.
Until now, it was believed that all galaxies formed gradually within large halos of dark matter.
Dark matter halos capture gas (atoms and molecules) into gravitationally bound structures.
Typically, 20% of this gas, at most, is converted into stars in galaxies.
However, the new findings challenge this view, revealing that massive galaxies in the early Universe may have grown far more rapidly and efficiently than previously thought.
“The question of ‘impossibly’ massive galaxies shortly after the Big Bang has vexed astronomers ever since the first Webb images,” said Dr. Ivo Labbé, an astronomer at Swinburne University of Technology.
“This is akin to finding a toddler weighing 100 kg. Webb has now proven monsters do roam the early Universe.”
Most sources found in the FRESCO survey fit existing models, but the astronomers also found three surprisingly massive galaxies, with stellar masses comparable to today’s Milky Way.
They have been named ‘red monsters,’ due to their high dust content, which gives them a distinct red appearance in the Webb images.
These are forming stars nearly twice as efficiently as their lower-mass counterparts and galaxies at later times.
“These findings raise new questions for galaxy formation theories, specifically the issue of ‘too many, too massive’ galaxies in the early Universe,” Dr. Labbé said.
“Current models fail to explain how it is possible star formation is so super-efficient, very early in the Universe”.
“The usual assumption is that exploding stars and supermassive black holes kill…
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