James Webb sniffs out 12

Apr 28, 2023

Using data from the James Webb Space Telescope, an international group of astronomers have discovered smog and smoke molecules indicative of early star formation in a galaxy only 1.5 billion years after the Big Bang.

In a universe around 13.7 billion years old, scientists are on the hunt for signals from early in its development to understand its evolution and current structure.

Since launch on Christmas Day 2021, the JWST has promised such insight by offering higher resolution observations than ever before.

Among its latest discoveries are observations of complex molecules known as polycyclic aromatic hydrocarbons – commonly found in soot and smoke here on Earth. A research team led by Justin Spilker, an assistant professor in the Texas A&M Department of Physics and Astronomy, has found these molecules associated with early star formation do not have uniform emissions for reasons yet to be explained.

In the galaxy known as SPT0418-47, the team found a good candidate for observing the early universe in development, owing to the gravitational lensing of the galaxy 12 billion light-years from Earth.

Gravitational lensing occurs when light from a distant object is bent by a massive object between it and the observer, sometimes offering more detail of the object.

In a statement, Spilker said: "By combining Webb's amazing capabilities with a natural 'cosmic magnifying glass,' we were able to see even more detail than we otherwise could. That level of magnification is actually what made us interested in looking at this galaxy with Webb in the first place, because it really lets us see all the rich details of what makes up a galaxy in the early universe that we could never do otherwise."

According to a paper published in the journal Nature this week, the team may have discovered the most distant known detection of complex aromatic molecules.

Spilker said: "These big molecules are actually pretty common in space. Astronomers used to think they were a good sign that new stars were forming. Anywhere you saw these molecules, baby stars were also right there blazing away."

But the new data shows areas with aromatic hydrocarbons but no star formation, while other areas have new stars forming but no signs of the indicative molecules.

Spilker promised to continue the search to uncover the process at hand in star formation in the early stages of the universe's evolution. "The only way to know for sure is to look at more galaxies, hopefully even further away than this one," he said. ®

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