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James Webb: the oldest and most distant galaxy ever observed

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Image source, NASA/ESA/CSA/STScI/Brant Robertson et al.

Screenshot, The distant galaxy (circled) is located next to another galaxy, but far behind it.

The James Webb Space Telescope has broken its own record by detecting the most distant galaxy known.

Called JADES-GS-z14-0, the collection of stars was discovered as it was just 290 million years after the Big Bang.

Put another way: if the Universe is 13.8 billion years old, it means that we are observing the galaxy when the cosmos was only 2% of its current age.

Webb used his huge 6.5m wide primary mirror and sensitive infrared instruments to make the discovery.

Astronomers say the most interesting aspect of the latest observation is not so much the large distance involved (surprising as that may be) but the size and brightness of JADES-GS-z14-0.

Webb measures the galaxy to be more than 1,600 light years across. Many of the most luminous galaxies generate most of their light through gas falling into a supermassive black hole. But the JADES-GS-z14-0 scale indicates that that is not the explanation in this case. Instead, researchers believe the light is produced by young stars.

“So much starlight implies that the galaxy is several hundred million times the mass of the Sun! This raises the question: how can nature create such a bright, massive and large galaxy in less than 300 million years?” said Webb astronomers Stefano Carniani and Kevin Hainline.

Dr. Carniani is affiliated with the Scuola Normale Superiore in Pisa, Italy, and Dr. Hainline is with the University of Arizona in Tucson, Arizona.

It was specifically designed to see further into the cosmos (and further back in time) than any previous astronomical tool.

One of their key objectives was to find the first stars to light up in the nascent Universe.

These giant objects, perhaps hundreds of times the mass of our Sun, were made solely of hydrogen and helium.

They are theorized to have burned bright but brief lives, forging into their nuclear nuclei the heaviest chemical elements known in nature today.

In JADES-GS-z14-0, Webb can see a significant amount of oxygen, indicating to researchers that the galaxy is already quite mature.

“The presence of oxygen at such an early stage in the life of this galaxy is a surprise and suggests that multiple generations of very massive stars had already lived their lives before we observed the galaxy,” added Drs Carniani and Hainline.

“JADES” in the object name stands for “JWST Advanced Deep Extragalactic Survey”. It is one of several observing programs that use the telescope to explore the first few hundred million years of the cosmos.

“z14” refers to “redshift 14”. Redshift is the term astronomers use to describe distances.

It is essentially a measure of how light coming from a distant galaxy has been stretched to longer wavelengths due to the expansion of the Universe.

The greater the distance, the greater the stretch. Light from the most primitive galaxies extends from ultraviolet and visible wavelengths to the infrared, the part of the electromagnetic spectrum to which James Webb’s mirrors and instruments were specifically tuned.

“We could have detected this galaxy even if it were 10 times fainter, meaning we could see other examples even earlier in the Universe, probably in the first 200 million years,” said Professor Brant Robertson of the University of California, Santa Fe. Cross. .

The discovery of JADES and its implications are described in several academic papers published on the arXiv preprint service.

Vaseline3 days ago

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