WASHINGTON: Since becoming operational last year, the James Webb Space Telescope has made groundbreaking observations involving some of the universe’s earliest galaxies. One might call them galactic infants.
But Webb has obtained even better data on galaxies a bit further along in development. Astronomers call these the galactic “teenagers.” And, as new research shows, they resemble human teenagers in certain respects, including by displaying growth spurts along with a bit of immaturity.
The researchers focused upon galaxies that formed about 2-3 billion years after the Big Bang event roughly 13.8 billion years ago that initiated the universe. The study averaged data obtained by Webb on light across various wavelengths emanating from 23 such galaxies - their “chemical DNA” - to paint a composite picture of teenage galactic characteristics.
“These teenage galaxies have very unique chemical DNA, which indicates that they have formed a decent number of stars - they’re fairly grown already - but still growing rapidly,” said Allison Strom, a professor of physics and astronomy at Northwestern University in Illinois and lead author of the study published this week in the Astrophysical Journal Letters.
These galaxies do not yet look or act the way galaxies do today, according to the researchers.
“They go through some important processes around this time - many of which we don’t yet understand and hope to soon understand better - which sets what type of galaxy they will become,” said astronomer and study co-leader Gwen Rudie of Carnegie Observatories in California.
The gas detected in star-forming regions - stellar nurseries - of teenage galaxies was much hotter, at about 24,000 degrees Fahrenheit (13,350 degrees Celsius), than observed in galaxies today.
“The temperature in these parts of galaxies is dominated by the young stars and the properties of the gas, so finding a different temperature means that there is something different about the stars and gas in the teenage galaxies,” Strom said.
The galaxies were observed glowing with eight elements - hydrogen, helium, oxygen, nitrogen, sulfur, argon, nickel and silicon.