Webb revealed features of a galaxy 25 billion light years away

The galaxy is currently 25 billion light-years away, but when light began to travel from it to us about 12.5 billion years ago, it was much closer, because the universe is expanding

The galaxy GS-9209, the oldest known quiescent galaxy.

Using the most powerful telescope to date, astronomers have identified a huge and highly clustered galaxy located 25 billion light-years away.

GS-9209, a galaxy that appeared only 600 to 800 million years after the Big Bang, has been identified as the earliest galaxy of its kind ever discovered, according to scientists.

Detailed features of GS-9209 were revealed for the first time using the James Webb Space Telescope, led by a team of researchers from Edinburgh.

Although it is about ten times smaller than the Milky Way, GS-9209's number of stars is similar to that of our own galaxy.

Their combined mass is around 40 billion times that of our Sun, and they formed quickly before star formation in GS-9209 stopped, the team said.

GS-9209 is the earliest known example of a galaxy that no longer forms stars - a "quiet galaxy". When the team observed it at the time point 1.25 billion years after the Big Bang, no stars had formed in the galaxy for about half a billion years.

GS-9209 observed by the James Webb Space Telescope near other galaxies.
Credit: G. Brammer, C. Williams, A. Carnall

The galaxy is currently 25 billion light-years away, but when light began to travel from it to us about 12.5 billion years ago, it was much closer, because the universe is expanding.

This means that although the estimated age of the universe is 13.8 billion years, it is possible to see things as far as 45 billion light years away, they added.

The analysis also shows that GS-9209 contains a central supermassive black hole five times larger than astronomers would expect in a galaxy with that number of stars. The discovery could explain why GS-9209 stopped forming stars, the team said.

As supermassive blacks grow, a huge amount of high-energy radiation is released, which can heat gas and push it out of galaxies. This could have caused the cessation of star formation in GS-9209, because stars form when clouds of dust and gas particles inside galaxies collapse under their own weight.

Dr. Adam Carnoll says: "The James Webb Space Telescope has already shown that galaxies grew larger and earlier than we thought in the first billion years of cosmic history. This study gives us the first truly detailed look at the properties of these ancient galaxies, and charts in detail the history of GS-9209 that was able to form as many stars as our own galaxy in just 800 million years after the Big Bang."

He continues: "The fact that we also see a very massive black hole in this galaxy was a big surprise, and adds a lot of weight to the idea that these black holes are what stopped star formation in ancient galaxies."

GS-9209 was first discovered in 2004 by Edinburgh PhD student Karina Caputi, who was then supervised by Professors Jim Dunlop and Ross McClure at the university's School of Physics and Astronomy. Caputi is now a professor at the University of Groningen, Netherlands.

for the scientific article

More of the topic in Hayadan:

• The green pea galaxies could help astronomers understand the early universe
• New research reveals that the early universe expanded much faster than today
• Astronomers are surprised by the unexpected size of galaxies in the early universe photographed by the James Webb Space Telescope