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The Triangulum Galaxy was recently captured by the James Webb Space Telescope. | Credit: NASA, ESA, CSA, STSCI
This story was provided by Live science, A sister side of Space.com.
Astronomers have discovered over a dozen “resting” galaxies that have their star development within the first billion years after the big bang.
The discovery made with data from the James Webb Space Telescope (JWST) illuminates a fascinating phase in life earlier galaxies and could provide more indications of how galaxies develop.
There are several reasons why galaxies may stop forming new stars. One thing is the presence of super massive black holes in their centers. These giants spend intensive radiation that heats and exhausted cold gas, the most important ingredient for star formation. In addition, larger neighboring galaxies can remove or heat this cold gas, which leads to star formation. As a result, these galaxies can remain resting or “deleted” indefinitely.
Another reason why galaxies become inactive is an outstanding feedback. Then the gas in the galaxy is heated and expelled due to star processes such as supernovas, intensive star winds or the pressure connected to star light. The galaxy thus goes through a temporary “quiet” time.
“This is usually a temporary phase that usually takes about 25 million years,” said Alba Covelo Paz, a doctoral student at the University of Geneva and the leading author of a new study that describes the results, to notify live science in an e -mail. For over millions of years, the gas that has been pushed out falls back in and the warm gas cools down again. As soon as there is enough cold gas again, the galaxy can form new stars.
While the resting phase is often observed in nearby galaxies, astronomers have only found four dormant galaxies in the first billion years of the universe. Of these, three masses had a billion solar mass and one had a mass of over 10 billion solar masses. The limited observations and scattered properties of resting galaxies were not enough to get a clear picture of early star formation.
With the help of the sensitive spectroscopic data from JWST, an international team of astronomers discovered 14 dormant galaxies with a variety of masses in the early universe, which shows that resting galaxies are not limited to low or very high mass areas.
The results were uploaded to the Preprint database Arxiv on June 27 and have not yet been checked by experts.
The Triangulum Galaxy has areas with active star formation. | Credit: NASA, ESA, CSA, STSCI
Take a breather
The researchers did not expect galaxies to be seen in the early universe. Since these galaxies are young, they should form a lot of new stars, astronomers thought. In an article from 2024, however, the researchers described the first discovery of a dormant galaxy in the early universe.
“The first discovery of a dormant galaxy in the early universe was such a shock because this galaxy had previously been observed with Hubble, but we couldn’t know that it was quiet until you,” said Paz.
This is because JWSTS Nirspec instrument can see both light from these galaxies, in contrast to the Hubble world space telescope, which have been reduced in almost infrared wave lengths, and also provide spectroscopic details about it.
Astronomers were curious to know why early galaxies stopped to form stars and whether this was common with a variety of star masses. One hypothesis was that the galaxies had star formation and then calm periods before they started again. Paz and her team searched for the galaxies that stood between star development. They used publicly available galaxy data in the DAWN JWST archive.
They examined the light of around 1,600 galaxies and searched for signs of new stars that do not form. They also concentrated on clear signatures of medium -sized or old middle -aged stars in the light of the galaxies. The team found 14 galaxies in the range of around 40 million to 30 billion solar masses that had stopped the star formation.
“We have now found 14 sources that support this Burtiness process and we found that all of them stopped the star formation between 10 [million] And 25 million years before we watched them, “said Paz. That means that these 14 galaxies pursue a stop-and-go fashion of star formation instead of constantly forming stars, and they have been quiet for at least 10 million years.
This relatively short snooze indicates that outstanding feedback such as supernovas or star winds became silent and you may restart her outstanding factories, said Paz.
However, there is still uncertainty, she added. “We cannot confirm it safely because we do not know how long they will rest, and if they happen to rest for another 50 million years, this would mean that the cause of their extinguishing is different,” said Paz.
This scenario would indicate that the galaxies are dead. Nevertheless, the current properties of these galaxies support a cycle of adjustments and starts.
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Because resting galaxies are so rare, much remains mysterious above them. However, astronomers hope that future observations will help to illuminate these scaly star factories. An upcoming JWST program called “Sleeping Beauties” will work on the discovery of dormant galaxies in the early universe, said Paz. With this program, astronomers can estimate how long a galaxy will stay in this quiet phase and helps them to understand the Bursty star formation process.
“There are still many strangers for us, but we are a step closer to struggle for this process,” said Paz.
