AMHERST — Astronomers from the University of Massachusetts played a key role in revealing the latest deep-field image from NASA’s James Webb Space Telescope, including some of the universe’s most distant galaxies.
“With these pictures, we’re looking back in time, 97% of the way to the Big Bang,” said Kate Whitaker, UMass assistant professor of astronomy.
The UMass team, spearheaded by postdoctoral researcher John Weaver, worked on processing, analyzing and correcting the data gathered by the Webb telescope from a region of space known as Pandora’s Cluster (Abell 2744). The cluster is found within the constellation Sculptor, a small, faint grouping of stars in the Southern sky.
Webb’s view displays three clusters of galaxies — already massive — coming together to form a megacluster. The combined mass of the galaxy clusters creates a powerful gravitational lens, a natural magnification effect of gravity, allowing much more distant galaxies in the early universe to be observed.
“We targeted this region because it’s one of the biggest cosmic magnifying glasses that we have,” Whitaker said.
In addition to magnification, gravitational lensing distorts the appearance of distant galaxies, so they look very different than those in the foreground. The galaxy cluster “lens” is so massive that it warps the fabric of space itself, enough for light from distant galaxies that passes through that warped space to also take on a warped appearance.
Whitaker said the UMass team’s job was to take the raw data and create a catalog of everything in the field, finding out “first and foremost how far away these galaxies are.”
Because space is expanding, the light from the galaxies that have been traveling the longest gets stretched closer and closer to infra-red. The most distant galaxies are invisible to the human eye, Whitaker said, but the Webb telescope, a million miles out in space, is able to uncover images with its infrared eyes from the first billion years of the universe, estimated at 13.8 billion years ago.
“We detected some 50,000 objects, including many distant galaxies behind the cluster itself, still in their infancy,” Weaver said in a release from UMass.
The project, dubbed UNCOVER and including chief investigators from universities in Pittsburgh and Melbourne, Australia, used Webb’s Near-Infrared Camera to capture the cluster with exposures lasting four to six hours, for a total of about 30 hours of observing time.
“My first reaction to the image was that it was so beautiful, it looked like a galaxy formation simulation,” astronomer Ivo Labbe of Melbourne’s Swinburne University of Technology stated. “We had to remind ourselves that this was real data, and we are working in a new era of astronomy now.”
The next step is to meticulously go through the imaging data and select galaxies for follow-up observation with the Near-Infrared Spectrograph, which will provide precise distance measurements along with many other details that will offer insights into the universe’s youth.
Whitaker said the UMass team, which includes graduate and undergraduate students, is excited for the next phase of the project. The undergrads will be focusing on the ancient globular clusters of stars between galaxies in Pandora’s Cluster, she said, while the grad students will be looking at galaxies from the so-called peak epoch, midway through the universe’s history when most stars were formed, how they form and why some of them stop forming new stars.
“We’re gearing up to do science,” Whitaker said.