The James Webb Space Telescope has captured an image of five galaxies in the process of merging into one vast system. This image shows them at a time when the Universe was only 800 million years old. This raises new questions about its early evolution.
An unexpected discovery by the James Webb Telescope
Astronomers from Texas A&M University have discovered a rare phenomenon of dense galaxy collisions in the early Universe, indicating that galaxies interacted and shaped their environment much earlier than scientists had previously thought.
Using observations from the James Webb Space Telescope, researchers have discovered the merger of at least five galaxies approximately 800 million years after the Big Bang, as well as evidence that the collision led to the redistribution of heavy elements beyond the galaxies themselves.
Before the James Webb Space Telescope was launched, astronomers assumed that complex galaxy mergers and the spread of oxygen and other products of stellar synthesis would become commonplace more than a billion years after the Big Bang. This discovery shows that these processes began much earlier than models had predicted.
Dr. Weida Hu, a postdoctoral researcher and lead author of the study, and Dr. Casey Papovich, professor of physics and astronomy, published their findings in the journal Nature Astronomy.
JWST’s Quintet
At this early stage in cosmic history, astronomers typically expect galaxies to be relatively small and isolated. The newly discovered system, dubbed JWST’s Quintet, demonstrates the interaction of several galaxies in a compact region of space surrounded by a halo of oxygen-rich gas.
Although separated by tens of thousands of light-years, the galaxies occupy an extremely compact region of space and formed stars at a rate of approximately 250 times the mass of the Sun per year, which is much higher than typical for galaxies of that time.
Distribution of heavy elements around galaxies
Researchers also discovered an extended halo of glowing gas connecting several galaxies. The gas emits light from ionized oxygen and hydrogen. The surprising result is that this gas is located outside the galaxies. Elements such as oxygen are formed only inside stars and are later ejected from galaxies during collisions.
The analysis by the team of scientists shows that enrichment occurred mainly under the influence of gravitational interactions during mergers, and not only under the influence of galactic winds, which is direct evidence that galaxy collisions shaped the environment in the early Universe.
Development of the theory of early galaxy evolution
Papovich notes that this discovery is important because it helps explain the growing discrepancy between astronomers’ predictions and what JWST is actually observing. “By showing that a complex, merger-driven system exists so early, it tells us our theories of how galaxies assemble—and how quickly they do so—need to be updated to match reality,” said Papovich.
This discovery may help explain why JWST is detecting more and more massive galaxies that are predominantly inactive just a few billion years after the Big Bang. If systems like JWST’s Quintet merge quickly and exhaust their gas supplies in the early stages, they could evolve into the massive galaxies observed in later cosmic epochs.
Future JWST observations will study the motion of gas and galaxies within the system, providing additional insights into how early cosmic structures formed.
According to phys.org
