Astronomers have discovered a very rare system in which at least five galaxies are fused from the early universe. It’s only 800 million years after the Big Bang. The surprising discoveries were made using data from James Webb Space Telescope (JWST) and Hubble Space Telescope.
Galaxy mergers play an important role in the galactic layers of the early universe. Although not generally seen, a merge system occurs and usually contains two galaxies. However, the newly identified merger called Quintet in JWST includes at least five galaxies and 17 galaxies masses.
“Finding such a system with five physically linked galaxies is extremely rare in both current simulations and observations,” says Weida Hu, a postdoctoral researcher at Texas A&M University. “Probability to detect at least one [multiple-galaxy merger] It’s so low that it’s likely that you’ve been “lucky” to identify this system very quickly,” Hu told Live Science in an email.
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These galaxies are called exhaust line galaxies because they have prominent signatures in the light, especially those released by hydrogen and oxygen.
Two Powers
The study, published August 15th in the journal Nature Astronomy, used a combination of JWST and Hubble data.
JWST’s near-infrared camera (NIRCAM) hinted at a large halo of gas around a group of galaxies. In other words, the five galaxies are not independent, but instead are physically connected and embedded in the same system.
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Some of these galaxies were previously detected using Hubble, but “only the JWST data tells us that five galaxies have the same redshift and interact with each other,” Hu added. (Redshift is a measure of cosmic distance, with a higher redshift corresponding to farther ancient objects. Redshift occurs when light emitted from distant objects extends to a longer red wavelength, crossing the universe, crossing the expanding universe.)
Hu suggested that there could be other faint or hidden galaxies linked to Quintet in JWST that have not yet been detected. However, discovering these galaxies may require sophisticated multi-wavelength observations.
Christopher Consolis, a professor of extragalactic astronomy at the University of Manchester who was not involved in the study, said early cosmic mergers, including two or more galaxies, were extremely rare.
“If you look at all galaxies, 20-30% will be merged. This will only be two galaxies. The proportion of these multiple merged systems is much lower, and although there are no statistics yet, it’s certainly less than 1%,” Conselice told Live Science.
The team discovered that the two major galaxies in the system appear to be separated by a distance of 43,300 light years, and found that the furthest pair of all galaxies in the system appears to be 60,700 light years apart. (For comparison, our Milky Way galaxies are from the end of about 100,000 light years to the end.)
“The fact that galaxies are spatially close is probably indicating that they merge,” Consolis said. “There is room for interpretation as to whether some objects are part of the same galaxy,” he added.
A good place far away
The system resembles the Quintet of Stephen, a local space counterpart, a merger of four galaxies, appearing in the same part of the sky, but with a fifth galaxy that is not fused.
“A striking similarity is the presence of a material bridge connecting the two galaxies in the Quintet of JWST. This is also a feature found in Stephan’s Quintet, indicating the tail of the tide dal produced by the Galaxy interaction,” Hu said. “However, the star formation rate for Quintet in JWST is much higher.”
All galaxies in Stephen’s Quintet are far older systems in nearby universes and therefore less active, but the galaxies in the JWST quintet are gas-rich and form new stars vigorously at higher speeds than expected for that period.
The Quintet of JWST features at least five galaxies and 17 galaxies, with a total of 10 billion solar stars. This study suggests that high mass and star formation rates indicate that merged galaxies could evolve into large stationary galaxies that occur approximately 1 billion to 1.5 billion years after the Big Bang. A stationary galaxy is a galaxy that stops forming new stars. Previous JWST research has detected some of them in the early universe, raising questions about how galaxies “dead” in the early universe.
Conselice said the future of integrating galaxies is a big problem. They become star-forming galaxies, but they can become less active or “dead” or passive over time. The future of the system also depends on whether the galaxy actively supplies black holes. This could allow the system to tweak star formation very quickly.
When the merge galaxy transforms into a dead system, JWST’s Quintet can potentially explain how large static galaxies are rapidly formed due to the merger of smaller Starburst galaxies in the early universe.
Hu noted that the Nircam image in JWST shows clear details of the object’s shape and structure, but does not provide accurate information such as the intensity of the spectral lines. Without these spectroscopic details, it is difficult to accurately measure the properties of the system, such as the metallicity, motion, dynamics, or the properties of the gases within these galaxies and masses.
If more systems, like the JWST Quintet, are found in future JWST investigations, researchers can examine how often these galaxy fusion groups appear, their properties, and examine the conditions in which they form. This allows researchers to verify whether these systems belong to rare classes predicted by current standard models of the universe, or whether they propose new mechanisms in operation.
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