Scientists have uncovered an intriguing story about the growth of galaxies involving mysterious “red monsters” that reveal new secrets of the young universe. An international team of experts led by the University of Geneva (UNIGE) has discovered three supermassive galaxies, each almost as massive as the Milky Way, that emerged within the first billion years after the Big Bang.

Galaxy formation theory

This discovery surprised scientists because it challenges the popular theory of galaxy formation. According to current models, galaxies are slowly growing into massive dark matter halos. These halos, invisible structures, attract gas that will eventually form stars. Traditionally, scientists believed that only 20% of this gas would form into stars in these galaxies.

But the UNIGE team’s findings show that these first massive galaxies were extremely efficient at creating stars. They grew at an extraordinary rate compared to later galaxies, producing stars much faster and in greater numbers than expected. This unexpected productivity suggests that the first galaxies grew in ways that scientists had not previously considered, prompting a revision of galaxy formation theories.

Three “red monsters”

The James Webb Space Telescope’s FRESCO program made this remarkable discovery possible. The beauty of the FRESCO program lies in its advanced instrument, the NIRCam/grism spectrograph, which allows precise measurements of galaxies’ distances and stellar masses. Thanks to JWST’s excellent capabilities, astronomers have been able to systematically study galaxies in the distant and early universe, including massive and dust-shrouded galaxies.

After examining the galaxies in the FRESCO survey, it was seen that most galaxies fit existing models. But the team found three surprisingly massive galaxies. Giant galaxies are now known as “red monsters” because of their high dust content, which gives them their unique red color in JWST images.

Uncovering hidden red monsters

The lead author of the study, Dr. Mengyuan Xiao is a postdoctoral researcher at the Department of Astronomy, Faculty of Science, UNIGE. Dr. To study red monsters, Xiao led CEA Paris-Saclay research director Dr. He joined forces with David Elbaz.

Dr. “Our findings revolutionize our understanding of galaxy formation in the early universe,” said Xiao. Dr. “The huge features of these red monsters were unlikely to be identified before JWST because they are optically invisible due to dust attenuation,” Elbaz said.

Studying the growth of galaxies over time

Using the James Webb Telescope, researchers have developed an innovative program that allows systematic analysis of a complete sample of galaxies with emission lines throughout the first billion years of cosmic history. This program allowed the team to obtain accurate distance estimates and reliable stellar mass measurements for a complete sample of galaxies. Pascal Esch is an associate professor at UNIGE’s Department of Astronomy and principal investigator of the observation programme.

“Our results highlight the extraordinary power of NIRCam/grism spectroscopy,” said Osh. “The instrument in the space telescope allows us to describe and study the growth of galaxies over time and get a clearer picture of how stellar mass accumulates throughout cosmic history.”

“Too many, too big” galaxies

The discovery of these massive galaxies challenges current ideas about how galaxies form. The findings reveal the existence of an unexpectedly large number of massive galaxies (very many, very massive galaxies) very early in the history of the universe. This suggests that current models may be missing certain processes or factors that allowed some galaxies to grow rapidly immediately after the Big Bang.

Future research directions

To better understand these giant galaxies, scientists will continue to observe them with powerful instruments such as JWST and ALMA. These tools could provide more detailed information and help find more such supermassive galaxies, deepening our understanding of galaxy formation in the early universe and potentially revising models of cosmic evolution. Future attempts promise to resolve persistent questions about the dark matter content of the Universe, star formation processes, and the dynamical behavior of galaxies on cosmic time scales.

Meaning of red monsters

JWST’s discoveries have greatly advanced our understanding of the origins of the universe, particularly by providing new insights into the early universe. These discoveries challenge existing paradigms of the evolution of the universe; It suggests that even in the new stages after the Big Bang, there was an environment ripe for the rapid growth and formation of red monsters.

Dr. “These results show that galaxies in the early universe were able to form stars with unexpected efficiency,” Xiao said.

“As we study these galaxies more deeply, they will provide new insights into the conditions that shaped the early universe. Red monsters are just the beginning of a new era in our study of the early universe.” The study was published in the journal Nature.