Astronomers discover oldest ‘dead’ galaxy in distant universe

(CNN) — Astronomers have discovered the oldest “dead” galaxy ever seen while studying the universe with the James Webb Space Telescope, and it is one of the deepest views of the distant universe ever captured by the observatory.

The galaxy existed when the universe was only about 700 million years old and its current age is about 13.8 billion years. But for some reason, star formation in the galaxy suddenly stopped, almost at the same rate at which star birth began 13 billion years ago, and researchers still haven’t discovered the reason.

A report describing the discovery appeared Wednesday in the journal Nature. According to the authors, studying the galaxy could reveal new insights about the early universe and the factors influencing star formation within galaxies.

“The first few hundred million years of the universe were a very active phase, in which many gas clouds broke up to form new stars,” Tobias Lusser, a doctoral student in extragalactic astrophysics at the institute and lead author of the study, said in a statement. Kavli Professor of Cosmology at the University of Cambridge. “Galaxies need abundant supplies of gas to form new stars, and the early universe was like an all-you-can-eat buffet.”

The research team was surprised to find a dead galaxy that essentially lived rapidly and died at a young age shortly after the Big Bang that created the universe.

A new image taken by the James Webb Space Telescope reveals a “dead” galaxy called JADES-GS-z7-01-QU in the distant universe. Zeds Collaboration

“It’s usually only later in the universe that we start to see galaxies stop making stars, whether because of black holes,” said study co-author Dr. Francesco D’Eugenio, an astrophysicist and postdoctoral research associate at Kavli. Or because of something else.” The Institute of Cosmology said in a statement.

What causes the death of galaxies?

Star formation stops when environmental factors deprive a galaxy of the gas needed for the birth of new stars.

Supermassive black holes or violent interactions of stars may be responsible for expelling gas from galaxies and immediately stopping star formation. Or, the process of birth of a star may consume so much gas that there is not enough time to replenish it to ensure that the process continues in the future.

“We are not sure that any of these scenarios can explain what we have now seen with the web,” said study co-author Roberto Maillino, professor of experimental astrophysics at the Cavendish Laboratory and the Kavli Institute of Cosmology at the University of Cambridge. he said. , in a statement.

“Until now, to understand the early universe, we have used models based on the modern universe. But now that we can look far back in time and see why star formation in this galaxy ended so early, models based on the modern universe may need to be revised,” Maolino said.

Webb’s observations revealed that the newly discovered galaxy, called JADES-GS-z7-01-QU, experienced a brief, energetic burst of star formation before star birth suddenly ceased. Lasted from 30 to 90 million years.

“Everything seems to happen faster and more dramatically in the early universe, and this may include galaxies moving from the star-forming phase to the quiescent or extinguishing phase,” said Looser.

an unusual observation

The dead galaxy revealed by the study is not the first discovered by astronomers, but it is the oldest galaxy ever observed.

Additionally, the galaxy also had a low mass, similar to that of a dwarf galaxy near the Milky Way, known as the Small Magellanic Cloud, which is still forming new stars. The previously observed dead galaxies were much larger, adding another complication to Webb’s search.

The newly discovered galaxy is billions of light years away from Earth. A light year is the distance a ray of light travels in one year, or more than 9.46 trillion kilometers. So Webb is essentially observing the galaxy as it existed in the past, and astronomers have not ruled out the possibility that it has essentially resurfaced and begun star formation again.

“We’re looking for other galaxies like this in the early universe, which will help us put some constraints on how and why galaxies stop forming new stars,” D’Eugenio said. “It may be the case that galaxies ‘die’ in the early universe and then come back to life; we will need more observations to help us figure this out.”