The most distant galaxy in which these chemicals are now known to exist has
been found by researchers to contain complex organic compounds. This galaxy
is more than 12 billion light-years from Earth. A new study provides crucial
insight into the intricate chemical interactions that take place in the
first galaxies in the early cosmos thanks to the capabilities of the
recently deployed James Webb Space Telescope and thorough analysis by the
research team.
Joaquin Vieira, a professor of astronomy and physics at the University of
Illinois Urbana-Champaign, and graduate student Kedar Phadke worked with
scientists from Texas A&M University and an international group of
scientists to distinguish between infrared signals produced by some of the
galaxy's more massive and large dust grains and those of the recently
discovered hydrocarbon molecules.
The magazine Nature has published the study's findings.
This endeavor began when Vieira was a graduate student researching
dust-obscured, extremely distant galaxies that were challenging to identify.
About half of the stellar energy generated in the cosmos is absorbed and
reemitted by dust grains, rendering infrared light from far-off objects very
dim or invisible to ground-based telescopes.
The gravitational lensing phenomenon, dubbed "nature's magnifying glass" by
the researchers, helped the JWST in the latest study. "This magnification
happens when two galaxies are almost perfectly aligned from the Earth's
point of view, and light from the background galaxy is warped and magnified
by the foreground galaxy into a ring-like shape, known as an Einstein ring,"
said Vieira.
Using the South Pole Telescope of the National Science Foundation, the
researchers concentrated the JWST on SPT0418-47, which was previously
described as a dust-obscured galaxy that gravitational lensing has enlarged
by a factor of 30 to 35. SPT0418-47 is 12 billion light-years away from
Earth, which corresponds to a time when the universe was 10% younger than it
is now, or less than 1.5 billion years old.
Prior to using gravitational lensing in conjunction with the JWST, Vieira
explained, "we could neither see nor spatially resolve the actual background
galaxy through all of the dust."
The interstellar gas in SPT0418-47 that is shrouded, according to
spectroscopic data from the JWST, is richer in heavy elements, which
suggests that previous star generations had already lived and perished. The
particular substance that the researchers found belongs to a class of
molecules known as polycyclic aromatic hydrocarbon, or PAH. These molecules
are present in combustion engine or forest fire exhaust on Earth. These
organic molecules, which are composed of carbon chains, are thought to be
the fundamental building blocks for the earliest forms of life, according to
the experts.
"We can see all of the regions where these smaller dust grains are
located—regions that we could never see before the JWST," Phadke said. "This
research is telling us right now—and we are still learning." "The new
spectroscopic data enable us to observe the galaxy's atomic and molecular
composition, providing very important insights into the formation of
galaxies, their lifecycle, and their evolution," the authors write.
We weren't prepared for this, Vieira stated. The ability to find these
intricate biological components at such a great distance is revolutionary
for future studies. We're only at the beginning stage of this work, learning
how to use it and discovering its potential. We are eager to watch how this
develops.
It's really wonderful that galaxies I found while researching and writing
my thesis will eventually be seen by the JWST, according to Vieira. "I am
appreciative of the money and assistance provided by the NSF, NASA, and
American taxpayers for both the SPT and the JWST. This finding would have
never been made without these tools.
Provided by
University of Illinois at Urbana-Champaign
