Posted by Heba El-Sayed
Sunday, March 12, 2023 04:00 PM
Astronomers recently used the James Webb Space Telescope to look at the structures of dust and gas that create stars in nearby galaxies, and some researchers have shared more about the findings and what they mean for our understanding of how galaxies form and evolve.
The project, called Physics at High Angle Resolution in Nearby Galaxies, or PHANGS, used James Webb to observe several galaxies like our own Milky Way to see how stars form within them.
“We are studying 19 of our closest isotopes to our galaxy,” one of the researchers, Eric Rosolowski of the University of Alberta, explained in a statement. “In our galaxy, we can’t do a lot of these discoveries because we’re stuck in it.”
Using Webb’s infrared instruments, researchers can look through clouds of dust and gas that would be opaque if viewed in the visible light range.
As objects get warmer, they emit more infrared light, so Webb’s instruments can see where pockets of warmer dust and gas lie, and how that relates to regions where stars are forming, Digitartlends reported.
“At 21 micrometers, which is the infrared wavelength used in the images collected, if you look at a galaxy you will see all these dust grains being heated up by starlight,” said Hamid Hassani, one of the researchers. “Infrared light is really key to tracking the cold, distant universe.”
The team has so far examined 15 galaxies, out of a total of 19 that they will examine for their project.
For the galaxies imaged so far, the researchers took information about the distribution and warmth of stars and determined the ages of those stars.
This came with some surprises, as many of the images they were seeing showed bright stars that were smaller than they expected.
“The age of these star populations is very young,” Al-Hassani said. “They are just starting to produce new stars and they are really active in star formation.”
It’s the star formation process that makes a galaxy grow and thrive, stars form a delicate balance of having enough material to form new stars, and the stellar wind created by young stars blows that material away.
“If you have star formation, that galaxy is still active,” Al-Hassani said. “You have a lot of dust and gas and all these emissions from the galaxy that lead to the next generation of the next massive star formation and keep the galaxy alive.”