Using the Webb telescope, astronomers discovered evidence of complex organic molecules in a galaxy more than 12 billion light-years away. The galaxy aligns almost perfectly with a second galaxy just 3 billion light-years from our perspective on Earth. In this false-color Webb image, the foreground galaxy is shown in blue, while the background galaxy is red. Organic molecules are highlighted in orange. Credit: J. Spilker/S. Doyle, NASA, ESA, CSA
These organic molecules are considered the building blocks of the first forms of life.
Researchers have detected complex organic molecules in a galaxy more than 12 billion light-years away from Earth, the most distant galaxy in which these molecules are now known to exist. Thanks to the capabilities of the recently launched James Webb Space Telescope (JWST) and careful analysis by the research team, a new study provides critical insight into the complex chemical interactions that occur in the earliest galaxies in the early universe. . University of Illinois Urbana-Champaign professor of astronomy and physics Joaquín Vieira and graduate student Kedar Phadke collaborated with researchers at Texas A&M University and an international team of scientists to differentiate between the infrared signals generated by some of the largest and most massive dust grains in the galaxy and those of the newly observed hydrocarbon molecules. “This project started when I was in graduate school studying very distant, hard-to-detect galaxies obscured by dust,” Vieira said. “Dust grains absorb and re-emit about half of the stellar radiation produced in the universe, rendering infrared light from distant objects extremely weak or undetectable through ground-based telescopes.”
In the new study, the JWST received a boost from what the researchers call “nature’s magnifying glass,” a phenomenon called gravitational lensing. “This magnification occurs when two galaxies are almost perfectly aligned from Earth’s point of view, and light from the background galaxy is warped and magnified by the ring-shaped foreground galaxy, known as the Einstein ring.” said Scallop.
The team focused JWST on SPT0418-47, an object discovered using the National Science Foundation’s South Pole Telescope and previously identified as a dust-obscured galaxy magnified by a factor of about 30 to 35 by gravitational lensing. SPT0418-47 is 12 billion light-years from Earth, which corresponds to a time when the universe was less than 1.5 billion years old, or about 10% of its current age, the researchers said. “Before we had access to the combined power of gravitational lensing and the JWST, we couldn’t see or spatially resolve the actual background galaxy through all the dust,” Vieira said. Spectroscopic data from JWST suggest that the obscured interstellar gas in SPT0418-47 is enriched in heavy elements, indicating that generations of stars have already lived and died. The specific compound the researchers detected is a type of molecule called a polycyclic aromatic hydrocarbon, or PAH.
On Earth, these molecules can be found in exhaust gases produced by combustion engines or forest fires. Being made up of carbon chains, these organic molecules are considered the building blocks of early life, the researchers said. “What this research tells us right now, and we’re still learning, is that we can see all of the regions where these smaller dust grains are found, regions that we could never see before JWST,” Phadke said. “The new spectroscopic data allow us to observe the atomic and molecular composition of the galaxy, providing very important information about the formation of galaxies, their life cycle and how they evolve.” “We didn’t expect this,” Vieira said. “Detecting these complex organic molecules at such a great distance is a game changer for future observations. This work is only the first step, and now we are learning how to use it and learn about its capabilities. We are very excited to see how it plays out.” this”. “It’s great that the galaxies I discovered while writing my thesis will one day be observed by the JWST,” Vieira said. “I am grateful to the US taxpayers, NSF, and NASA for funding and supporting both the SPT and JWST. Without these instruments, this discovery could never have been made.”