The James Webb Space Telescope (JWST) has spotted a trio of gigantic “red monster” galaxies in the early universe, and they could rewrite our understanding of how stars and galaxies first formed.
The enormous galaxies — each 100 billion times the mass of our sun and nearly as massive as the Milky Way — are more than 12.8 billion years old, having formed within a billion years of the Big Bang.
This means that the stars within these galaxies coalesced at a bafflingly fast rate; so fast, they challenge existing models of how galaxies form. The researchers published their findings Nov. 13 in the journal Nature.
“Finding three such massive beasts among the sample poses a tantalising puzzle,” study co-author Stijn Wuyts, a professor of astronomy at the University of Bath in the U.K., said in a statement. “Many processes in galaxy evolution have a tendency to introduce a rate-limiting step in how efficiently gas can convert into stars, yet somehow these Red Monsters appear to have swiftly evaded most of these hurdles.”
The conventional view among astronomers is that galaxies form within gigantic halos of dark matter, whose powerful gravity sucks ordinary matter such as gas and dust inwards before compressing it to form stars.
Typically, this is seen as a fairly inefficient process, with just 20% of the infalling gas ending up as stars. The discovery of the red monsters confounds this view, with as much of 80% of their gas seemingly converted into bright young stars.
“These results indicate that galaxies in the early Universe could form stars with unexpected efficiency,” study lead author Mengyuan Xiao, a researcher at the University of Geneva, said in the statement. “As we study these galaxies in more depth, they will offer new insights into the conditions that shaped the Universe’s earliest epochs. The Red Monsters are just the beginning of a new era in our exploration of the early Universe.”
The red monsters, which get their nickname from their distinctive red glow, were spotted using the JWST’s Near Infrared Camera (NIRCam), a spectrograph that studies distant light by splitting it into its constituent parts. The JWST’s infrared capabilities enable it to peer deeper and into more dust-obscured parts of the early universe than other telescopes.
The researchers’ next steps will be to make further observations of the red monsters using both the JWST and Chile’s Atacama Large Millimeter Array (ALMA) telescope. The discoveries also raise questions for astrophysicists working on models of how early galaxies evolved, who may have to consider unique processes that enabled giant galaxies to grow with such efficient star formation.
“Already in its first few years of operation, JWST has thrown us a couple of curveballs,” Wuyts said. “In more ways than one, it has shown us that some galaxies mature rapidly during the first chapters of cosmic history.”
