Webb Space Telescope detects universe's most distant complex organic molecules

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.