Hubble telescope discovers 6 mysteriously dead massive galaxies from the first universe

Scientists studying the first galaxies were stunned earlier this year when they discovered six massive galaxies that appear to have died during the most active period of star birth in the universe. NASA’s Hubble Space Telescope spied on the six galaxies, which appeared to be running out of cold hydrogen gas needed to make stars while most other galaxies were producing new stars at a rapid rate.

“At this point in our universe, all galaxies should form a lot of stars. This is the peak period of star formation,” Kate Whitaker, assistant professor of astronomy at the University of Massachusetts at Amherst and lead author of a recent study on the six galaxies. , said in a press release. “So what happened to all the cold gas in these galaxies so early?”

Without the cold hydrogen gas needed to power stars and give birth to new ones, galaxies are essentially dead. They are also unable to rejuvenate, even though they have absorbed smaller galaxies and nearby gas clouds. Whitaker said the act of absorbing only “inflates” the dead galaxies.

But why they died in the first place is still a mystery.

“Did a supermassive black hole in the center of the galaxy ignite and heat all the gas?” Whitaker posed. “If so, the gas could still be there, but now it’s hot. Or it could have been expelled and now it’s being prevented from building up in the galaxy. Or has the galaxy used it all up. and the supply is cut off? “

“These are some of the open questions that we will continue to explore with new observations down the road,” Whitaker added.

Hubble was used by astronomers to locate galaxies, and then, using the Atacama Large Millimeter / submillimeter Array (ALMA) in northern Chile, researchers were able to detect whether or not the galaxies contained the cold dust that signals l existence of cold hydrogen gas.

But because the galaxies were so old and so far away, scientists wouldn’t have been able to spot them without a technique known as the “gravitational lens,” NASA explained. The team used clusters of super-massive galaxies closer to Earth as natural telescopes. The light from background objects is amplified by the gravity of these clusters. According to NASA, when very distant galaxies lie behind a cluster, they appear stretched and magnified in images, helping astronomers see details that would otherwise be lost without the magnification of galaxy clusters.

“Using a powerful gravitational lens as a natural telescope, we can find the distant, most massive and first galaxies to stop star formation,” Whitaker said. “I like to think of it as doing science in the 2030s or ’40s – with powerful next-generation space telescopes – but today combining the capabilities of Hubble and ALMA, which are bolstered by a powerful lens.”

Mohammad Akhshik, principal investigator of the Hubble Observation Program, said the team had assembled the largest sample to date of these rare and dead galaxies in the early universe.