Astronomers have discovered the oldest “dead” galaxy in the distant Universe
(CNN) — Astronomers have discovered the oldest “dead” galaxy ever observed while studying space with the James Webb Space Telescope, in one of the observatory’s deepest images of the distant Universe to date.
The galaxy existed when the universe was only about 700 million years old, and its current age is about 13.8 billion years. But something caused the galaxy to suddenly stop star formation almost as quickly as star birth began more than 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 can provide new insights into the early Universe and the factors influencing star formation within galaxies.
“The first few hundred million years of the Universe’s existence were a very active phase, with many gas clouds collapsing to form new stars,” study lead author Tobias Luser, a doctoral student in extragalactic astrophysics at the Institute, said in a statement. Kavli from Cambridge University Cosmology. “Galaxies need a rich supply of gas to form new stars, and the early Universe was like an all-you-can-eat buffet.”
The research team was surprised to discover a dead galaxy that essentially lived fast and died young shortly after the Big Bang that created the Universe.
A new image from the James Webb Space Telescope shows a dead galaxy called JADES-GS-z7-01-QU in the distant Universe. JADES Collaboration
“It’s usually only later in the universe that we start to see galaxies stop forming stars, whether due to a black hole or something else,” said study co-author Dr. Francesco D’Eugenio, an astrophysicist and Kavli Fellow. The Institute of Cosmology reports this.
What causes the death of galaxies?
Star formation stops when environmental factors deprive the galaxy of the gas needed to support the birth of new stars.
Supermassive black holes or violent stellar interactions may be to blame for the ejection of gas from galaxies, quickly stopping star formation. Or the act of birthing a star may consume so much gas that there is no time to replenish it enough for the process to continue into the future.
“We are not sure whether any of these scenarios can explain what we are now seeing with Webb,” said study co-author Roberto Maiolino, professor of experimental astrophysics at the Cavendish Laboratory and the Kavli Institute of Cosmology at the University of Cambridge. , 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 much further into the past and see that star formation in this galaxy stopped so quickly, models based on the modern Universe may have to be revised,” Maiolino added.
Webb’s observations revealed that the newly discovered galaxy, called JADES-GS-z7-01-QU, experienced a brief, energetic burst of star formation that lasted between 30 and 90 million years before star birth suddenly stopped.
“Everything seems to happen faster and more dramatically in the early Universe, and this may include galaxies transitioning from a star-forming phase to a quiescent or decaying phase,” Loser said.
Unusual observation
The dead galaxy discovered in the study is not the first that astronomers have discovered, but it is the oldest one observed so far.
Moreover, the galaxy also had a low mass, similar to a dwarf galaxy near the Milky Way known as the Small Magellanic Cloud, where new stars are still forming. Previously observed dead galaxies were much larger, adding another uncertainty to Webb’s discovery.
The newly discovered galaxy is billions of light years 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 haven’t ruled out the possibility that it has essentially resurrected itself and started forming stars again.
“We’re looking for other similar galaxies 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 that galaxies in the early Universe ‘die’ and then come back to life; we will need more observations to help us understand this.”