James Webb telescope discovers ‘exceptionally rare’ 5-galaxy crash in the early universe
Astronomers have discovered an incredibly rare system in which at least five galaxies in the early universe merge – only 800 million years later Big Bang. The remarkable discovery was made using data from the James Webb space telescope (JWST) and the Hubble space telescope.
Galaxy mergers play a key role in the formation of galaxies in the early universe. Although not commonly observed, merger systems occur, generally involving two galaxies. However, the newly identified merger, nicknamed jwst quintet, contains at least five galaxies and 17 clusters of galaxies.
“Finding such a system with five physically linked galaxies is exceptionally rare, both in current simulations and in observations,” said the main study of the study Weida HuPostdoctoral researcher at Texas A&M University. “The probability of detecting even a [multiple-galaxy merger] is quite weak, which raises the possibility that we had a “chance” in the identification of this system so early, “said Hu to Live Science in an email.
These galaxies are called emission galaxies because they have important signatures in their light, in particular those issued by hydrogen and oxygen, which are signs revealing new stars.
The power of two
Research, published on August 15 in the journal Natural astronomyused a combination of JWST and Hubble data.
The JWST Infrared (Nircam) near infrared camera has suggested a large gas halo around the group of galaxies, which meant that the five galaxies are not independent but are rather physically connected and integrated into the same system, Hu.
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Although some of these galaxies were previously detected using Hubble, “only JWST data tell us that the five galaxies have the same red time and interact with each other,” added Hu. (The lag towards red is a measurement of the cosmic distance, with higher red offsets corresponding to more distant ancient objects. The red shift occurs when the light emitted by distant objects extends into longer and redest wavelengths while crossing the expansion universe.)
Hu suggested that there may be other weak or hidden galaxies linked to the jwst quintet that has not yet been detected. But the discovery of these galaxies may require advanced observations of wavelength.
The first mergers in universes involving more than two galaxies are extremely rare, said Business of ChristopherProfessor of extragalactic astronomy at the University of Manchester who was not involved in the study.
“If you look at all the galaxies, then 20 to 30% of them will be in a merger. It will only be two galaxies. The fraction of these multiple merger systems will be much lower, and we do not yet have statistics, but certainly less than 1%,” said directly.
The team noted that the two main galaxies of the system seem to be separated by a distance of 43,300 light years, and the most distant pair among all the system galaxies seems to be at 60,700 light years. (As a comparison, our Milky Way The galaxy is around 100,000 light years from start to finish.)
“The fact that galaxies are spatially close to each other is the indication they probably merge,” said Conselice. “There is a place for interpretation as to whether certain objects could be part of the same galaxy,” he added.
The distant cousin
This system is similar to its local universe counterpart, Stephan quintetwhich is a fusion of four galaxies, with a fifth galaxy which appears in the same part of the sky but which does not merge.
“A striking similarity is the presence of a material bridge connecting two galaxies in the JWST quintet – a characteristic also seen in the quintet of Stephan, indicating tidal tails produced by the interaction of the galaxy,” said Hu. “However, the JWST quintet training rate is much higher.”
While all the Galaxies of Stephan’s Quintet are much older systems in the neighboring universe, and are therefore less active, the galaxies of the JWST quintet are rich in gas and vigorously form new stars at a higher pace than expected for this period.
The jwst quintet, with at least five galaxies and 17 clusters of galaxies, has a total stellar mass of 10 billion suns. The study suggests that the high mass and the star formation rate indicate that the merger galaxies can evolve towards a massive rest galaxy, occurring about 1 billion to 1.5 billion years after the Big Bang. The galaxies at rest are those which cease to form new stars. Previous JWST studies have detected several of them in the first universe, which raised questions about how galaxies could become “dead” so early in the universe.
Conselice said that the future of the merger of galaxies is a big question. They could end up like galaxies forming stars, but with less activity, or they could simply become “dead” or passive over time. The future of the system will also depend on the question of whether the galaxies actively host black holes, which could push the system to extinguish the formation of stars very quickly.
If the merged galaxies are transformed into a dead system, the JWST quintet could potentially explain how quickly the galaxies can form quickly thanks to the fusion of smaller and star galaxies in the early universe.
Hu noted that JWST Nircam images show clear details of the forms and structures of objects, but they do not offer precise information such as the intensity of spectral lines. Without these spectroscopic details, it is difficult to precisely measure the properties such as the metallicity, movement and dynamics of the system, or the nature of the gas inside these galaxies and tufts.
If more systems like the JWST quintet are found in future JWST surveys, researchers can study how frequency these merged galaxies appear, their nature and examine the conditions under which they are formed. This will allow researchers to verify whether these systems belong to a rare class that the current standard model of the predicted universe or if they suggest new mechanisms in action.
