The James Webb Space Telescope (JWST) has discovered what could be the earliest star clusters in the universe.
JWST discovered the five proto-globular clusters – swarms of millions of stars held together by gravity – within the Cosmic Gems arc, a galaxy that formed just 460 million years after the Sun’s birth. Big bang.
The Cosmic Gems arc gets its name from its appearance: when viewed from our solar system, the star-studded galaxy looks like a hair-thin crescent moon due to the powerful gravitational influence of a foreground galaxy, which magnifies and distorts the appearance of the distant galaxy.
The galaxy is the most magnified region seen in the first 500 million years of our universe, giving astronomers unprecedented insight into how the stirrings of the first stars formed galaxies during the cosmic dawn.
Cosmic dawn is the time that spans the first billion years of the universe. About 400 million years after the Big Bang, the era of reionization began, in which light from rising stars strips hydrogen of its electrons. fundamental reshaping of galaxy structures.
‘The early universe is nothing like we expected,’ says lead author Angela Adamoan astronomer at Stockholm University told LiveScience. “Galaxies are brighter, they form stars at a rapid pace, and they do so in massive and dense star clusters. We are building a new understanding of how early galaxies formed.”
The researchers published their findings in the journal on June 24 Nature.
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Lights on at cosmic below
As stars form, they throw away material in the form of winds and jets of ionized plasma – a process known as stellar feedback.
“In order to form these five-star clusters, this small galaxy had to do so with very high efficiency,” Adamo said. “The stellar feedback from the stars in star clusters must have been enormous.”
Scientists discovered the Cosmic Gems arc in 2018 using the Hubble Space Telescope. Normally, galaxies from such an early date emit light that is far too faint to be detected by telescopes. But a phenomenon called gravitational lensing can help astronomers view them.
As Einstein outlined in his theory of general relativity, gravity is the curvature and distortion of space-time in the presence of matter and energy. This curved space in turn sets the rules for how energy and matter move.
This means that although light travels in a straight line, light can be bent and magnified by the presence of gravity. In this case, the galaxy SPT-CL J0615-5746 lies between the Cosmic Gems arc and our solar system, bending and magnifying the light from the early galaxy so it can be viewed through telescopes.
By focusing JWST on this region of curved space, astronomers observed the cosmic gemstone arc in unprecedented detail, resolving the five globular clusters nestled within it. They found that the clusters were incredibly dense, roughly three orders of magnitude denser than star-forming regions observed closer to Earth.
The clusters are among the first ever observed. But it’s still unclear whether they are the first to exist, Adamo said.
“In principle, I would expect star formation to occur in clusters, even in quite primordial galaxies,” she added. ‘But to shape [massive] proto-globular clusters, the host galaxy must be able to create and retain sufficient mass of gas. So it all depends on how quickly primordial galaxies can grow.”
To learn more about the first embers of the cosmos in the region, the researchers will conduct a spectroscopic analysis using the JWST. This will allow astronomers to reconstruct the physical properties of the clusters, further constrain their ages and trace the impact of the clusters’ stars on their wider galaxy.