The researchers, however, do not rule out the possibility of the dead galaxy roaring back to life
Photo: JADES Collaboration
The James Webb Space Telescope (JWST) has captured the oldest-known dead galaxy, which stopped forming stars 13 billion years ago, according to a new study.
This dead galaxy was spotted when the universe was just 700 million years old, the study published in Nature stated. The universe sprang into existence about 13.8 billion years ago.
This galaxy lived a fast and furious life. It experienced a short and intense period of star formation between 30 and 90 million years. But between 10 and 20 million years before Webb’s observation, star formation stopped abruptly.
These findings, according to the researchers, could provide clues into how and why galaxies stop forming new stars and whether the factors affecting star formation have changed over billions of years.
“Understanding how star formation in galaxies is regulated and stops is one of the key open problems in modern astrophysics,” the researchers wrote in their study.
Previously, the Hubble telescope spotted six early, massive, “dead” galaxies that had lost cold hydrogen gas needed to make stars. About three billion years after the Big Bang, this galaxy experienced active star birth.
With the help of the JWST, researchers can identify dead galaxies with higher redshift and lower mass than before. As the universe expands, galaxies move away from us. As a result, light from these galaxies is shifted to longer (and this means redder) wavelengths — astronomers call this ‘red-shifted’.
The mass of this newly discovered dead galaxy is comparable to Small Magellanic Cloud (SMC), a dwarf galaxy near the Milky Way.
The researchers think the first few hundred million years witnessed lots of gas clouds collapsing to form new stars.
“Galaxies need a rich supply of gas to form new stars, and the early universe was like an all-you-can-eat buffet,” Tobias Looser from the Kavli Institute for Cosmology, the paper’s first author, said in a statement.
“It’s only later in the universe that we start to see galaxies stop forming stars, whether that’s due to a black hole or something else,” Francesco D’Eugenio from the Kavli Institute for Cosmology, said in a statement.
The paper explained that star formation can be slowed or stopped due to different factors when the galaxy runs out of gas needed to form new stars.
Internal factors, such as a supermassive black hole or feedback from star formation, can push gas out of the galaxy, causing star formation to stop rapidly, they added.
Alternatively, gas that was quickly consumed by star formation might not have been replenished by fresh gas from the surroundings of the galaxy, leading to starvation of gas.
“Everything seems to happen faster and more dramatically in the early universe, and that might include galaxies moving from a star-forming phase to dormant or quenched,” Looser explained.
The researchers, however, do not rule out the possibility of the dead galaxy roaring back to life. Further observations can provide more clues.
The team is also looking for other similar galaxies that existed in the early universe to understand how and why galaxies stop forming new stars.
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