Scientists find complex aromatic molecules in young, distant galaxy

Abstract

Astronomers have detected polycyclic aromatic hydrocarbons (PAHs) in a galaxy observed as it was less than 1.5 billion years after the Big Bang, according to a new report ( Nature 2023, DOI: 10.1038/s41586-023-05998-6 ). The findings demonstrate the James Webb Space Telescope’s (JWST) prowess for probing chemistry in deep time. While earthbound chemists might find these complex organic molecules in soot or smog, astronomers seek out PAHs in space to guide them toward newborn stars. When stars first form, they blast out intense ultraviolet (UV) radiation. That UV light photoactivates PAHs, which emit infrared (IR) radiation in turn. So when IR telescopes spot emissions of PAHs, it’s likely because a blazing young star lit them up, says Justin Spilker, an astrophysicist at Texas A&M University. That’s what the Spitzer Space Telescope and others have observed in nearby galaxies, but limited instrument sensitivity has prevented astronomers from glimpsing PAHs in our