The potent satellite observatory observed four galaxies as recently as 350
million years after the Big Bang.
The oldest galaxies ever seen have been seen by the James Webb Space
Telescope (JWST).
According to two recent studies, astronomers can now be sure that the light
from these galaxies has been moving to Earth for more than 13.4 billion
years. The findings illustrate the quick emergence of the first generations
of galaxies and reveal that these galaxies lived in the cosmos when it was
only 350 million years old.
The need to demonstrate that these galaxies do, in fact, live in the early
cosmos was critical. According to Emma Curtis-Lake, an astrophysicist at the
University of Hertfordshire in England and a co-author of one of the new
investigations, "it's very feasible for closer galaxies to pose as very faraway
galaxies.
"Seeing the spectrum exposed as we had anticipated, it confirmed that these
galaxies are at the true edge of our field of vision, some of which are
farther away than Hubble could see! It is an incredibly thrilling
accomplishment for the cause, according to Curtis-Lake.
The finding supports JWST's capacity to carry out one of its most crucial
jobs, namely investigating the early universe using light whose wavelength
has been stretched by the universe's expansion due to how far it has
traveled. Redshift refers to the lengthening of light; the further toward
the red end of the electromagnetic spectrum the light is shifted by the
universe's growth. As a result, redshift can be used to calculate distance,
and early galaxies should have light that exhibits severe redshifts and is
stretched all the way into the infrared, which is a speciality of the
JWST.
The $10 billion telescope has so far discovered a number of exceptionally
high-redshift candidate galaxies, but spectroscopy still needs to be used to
verify these findings.
Because spectroscopy can identify the distinctive signatures of particular
elements, it can be used to distinguish between distant, more recent
galaxies that might share comparable characteristics and early galaxies.
Early planets lack stronger elements like oxygen, nitrogen, and carbon and
are primarily made of hydrogen and helium. This is due to the fact that they
have not yet been enriched by the heavier elements that stars produce
through nuclear fusion and then spread when they supernova and expire.
The four galaxies designated JADES-GS-z10-0, JADES-GS-z11-0,
JADES-GS-z12-0, and JADES-GS-z13-0 do in fact have extreme redshifts,
ranging from 10.3 to 13.2, according to the researchers' analysis of data
obtained from JWST's near-infrared camera (NIRCam) and Near-Infrared
Spectrograph (NIRSpec) instrument. (JADES, by the way, stands for "JWST
Advanced Deep Extragalactic Survey.")
This result was reached because these galaxies' spectra lack the
distinctive trace of heavy elements like carbon, indicating that JWST is
viewing them as they were when the universe was only 300–500 million years
old. (The universe is currently about 13.8 billion years old.)
Brant Robertson, a co-author and part of the NIRCam scientific team, said
in the statement, "For the first time, we have found galaxies only 350
million years after the Big Bang, and we can be completely sure of their
amazing distances. It is a unique experience to discover these early
galaxies in such exquisitely gorgeous pictures.
The data originate from the first round of JADES studies, which focused on
the Ultra Deep Field, a small region of the sky that has been studied for
about 20 years by the Hubble Space Telescope. Around 100,000 galaxies can be
found in this area of the heavens, each captured at a specific time in its
existence, possibly billions of years ago.
The Ultra Deep Field was studied with NIRCam over the course of more than
ten days of the JWST mission, with observations made in nine distinct
infrared wavelengths. The NIRSpec device then collected data for 28 hours
over the course of three days. JWST thus provided scientists with the
information they required to precisely measure each galaxy's redshift and
disclose the characteristics of the gas and stars within each one, as well
as delivering extremely sensitive and clear pictures of the area.
According to Marcia Rieke, the primary scientist for NIRCam at the
University of Arizona, "These results are the culmination of why the NIRCam
and NIRSpec teams joined together to execute this observing program."
The two papers were published today (April 4) in the
journal Nature(opens in new tab). The researchers first reported the results
in December 2022, when they presented them at a conference.
