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Webb discovers the most distant galaxy ever seen

04 июня 2024

Webb discovers the most distant galaxy ever seen

The James Webb telescope has discovered the most distant known galaxy, which appeared just 290 million years after the Big Bang — a scientific article by a group of astronomers. If the universe were a two—hour movie, then this galaxy would be its first two and a half minutes - astronomer Kevin Heinlein. The galaxy is estimated to be 1.6 thousand light-years across, and its mass is several hundred million times that of the Sun. Judging by the data obtained, oxygen was present in the galaxy, while a number of massive stars in it had already ended their existence. We are talking about a galaxy called JADES-GS-z14-0. It was first discovered in early 2023, but astronomers took time to confirm the information about the new record. The previous record belonged to the galaxy JADES-GS-z13-0, which existed 320 million years after the Big Bang.

How JADES-GS-z14-0 was discovered

In October 2023 and January 2024, a group of astronomers used the James Webb Space Telescope to observe galaxies as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. The Webb NIRSpec instrument (Near infrared spectrograph) has discovered a record-breaking galaxy known as JADES-GS-z14-0.

JADES-GS-z14-0 appears to us as it existed just 290 million years after the Big Bang, when the universe was in its infancy. This amounts to a redshift of about 14, which is an indicator of how much the galaxy's light has been stretched as a result of the expansion of the universe.

The authors of the study are Stefano Carniani from the Higher Normal School in Italy and Kevin Heinlein, associate research professor at the Steward Observatory at the University of Arizona.

"Judging by the images, the diameter of the source is more than 1,600 light-years, which proves that the light we see comes mainly from young stars, and not from radiation near a growing supermassive black hole," the scientists said in a joint statement. "This amount of starlight means that the mass of the galaxy is several hundred million times the mass of the Sun. The question arises: how could nature create such a bright, massive and large galaxy in less than 300 million years?

"JADE researcher Jake Helton from the Steward Observatory and the University of Arizona also found that JADES-GS-z14-0 was detected at longer wavelengths using the Webb MIRI instrument (a mid-infrared instrument), which is a remarkable achievement given its remoteness.

"MIRI observations cover wavelengths of light emitted in the visible light range, which are redshifted and inaccessible to Webb instruments in the near infrared range.

"Jake's analysis shows that the brightness of the source obtained by observing MIRI exceeds what could be obtained based on measurements by other Webb instruments, which indicates the presence of strong ionized gas radiation in the galaxy in the form of bright emission lines of hydrogen and oxygen.

"The presence of oxygen at such an early stage in the existence of this galaxy is unexpected and suggests that several generations of very massive stars had already lived their lives before we observed the galaxy. "All these observations taken together tell us that JADES-GS-z14-0 is not like the types of galaxies whose existence was predicted by theoretical models and computer simulations in the earliest universe."

Source: BBC Sky at night