The James Webb Space Telescope (JWST) has observed the oldest galaxy ever observed.
Astronomers are now sure that the light is from this galaxy It had traveled to Earth more than 13.4 billion years ago, two new studies report. The results show that these galaxies are inhabited Universe When it is less than 350 million years old, it marks the rapid emergence of the first generation of galaxies.
“It is very important to prove that these galaxies did live in the early universe. It is very likely that a closer galaxy masquerading as a very distant one,” Emma Curtis Lake, a co-author on one of the new studies and an astronomer at the University of Hertfordshire in England, said in a paper. statement (Opens in a new tab).
“Seeing the open spectrum as we expected, confirms that these galaxies are at the true edge of our view, and some are further away from Hubble i can see! “This is a very exciting mission accomplishment,” said Curtis Lake.
Related: James Webb Space Telescope: Everything you need to know
This discovery underscores JWST’s ability to perform one of its most important tasks yet – studying the early universe through light that travels so long that the expansion of the universe lengthens its wavelength. This expansion of light is called red shift; The longer light travels, the more the universe expands towards the red end of the electromagnetic spectrum. This means that redshift can be used as a measure of distance, and that early galaxies must have had light that exhibited extreme redshifts, with light extending into the infrared range—specifically the JWST.
To date, the $10 billion observatory has identified several candidate galaxies with very high redshifts, but these observations must be confirmed using spectroscopy.
Spectroscopy can be used to distinguish between early galaxies and closer and newer galaxies that may have similar characteristics, as spectroscopy can identify the characteristic fingerprints of certain elements. Early galaxies were composed mostly of hydrogen and helium, and lacked heavier elements such as oxygen, nitrogen and carbon. This is because they have not been enriched with the heavy elements that make them up bintang by nuclear fusion and then scattered as these stars died and left Supernova.
The researchers’ analysis of data collected from the JWST Near Infrared Camera (NIRCam) and Near Infrared Spectroradiometer (NIRSpec) instruments allowed them to determine the four galaxies designated JADES-GS-z10–0, JADES-GS-z11–0, have JADES-GS -z12–0 and JADES-GS-z13–0 have a very intense redshift, going from 10.3 to 13.2. (JADES stands for “JWST Advanced Deep Extragalactic Survey, by the way.”)
They came to this conclusion because the spectra of these galaxies lack clear signatures of heavy elements like carbon, meaning JWST sees them as they did when the universe was only 300 to 500 million years old. (The universe is currently about 13.8 billion years old.)
“For the first time, we have detected a galaxy just 350 million years after the Big Bang, and we are quite confident of its extraordinary distance,” said Brant Robertson, co-author and member of the NIRCam science team, in the release. “Finding these early galaxies in such beautiful images is a special experience.”
The observations come from the first round of JADES observations, directed at a small region of the sky known as the Ultra Deep Field that the Hubble Space Telescope has been investigating for nearly two decades. This patch of sky contains about 100,000 galaxies, each of which was discovered at some point in its history, perhaps billions of years ago.
The researchers used more than 10 days of JWST mission time to study the ultra-deep field with NIRCam, observing it in nine different infrared colors. This was followed by 28 hours of data collection performed by the NIRSpec instrument over three days. Because of this, JWST has provided highly sensitive and sharp images of the region, and has also provided astronomers with the data they need to obtain an accurate measure of each galaxy’s redshift and reveal the nature of the gas and stars in each of them.
“These results are the pinnacle of why the NIRCam and NIRSpec teams worked together to implement this monitoring program,” said Marcia Rieke, NIRCam principal investigator from the University of Arizona.
Both papers were published today (April 4) in Nature magazine (Opens in a new tab). The researchers first announced their results in December 2022, when they presented them at a conference.
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