February 15, 2023

The most recent deep field image from NASA's James Webb Space Telescope, showing previously unseen details in a region of space known as Pandora's Cluster, has been made public by astronomers (Abell 2744). Three existing huge clusters of galaxies are seen merging to form a megacluster in Webb's vision. By acting as a natural magnifying glass, the galaxy clusters' combined mass produces a strong gravitational lens that makes it possible to detect many more distant galaxies in the early universe.

The Hubble Space Telescope of NASA has only before conducted extensive research on Pandora's center core. In order to create a balance between breadth and depth that would open up a new field in the study of cosmology and galaxy development, astronomers combined Webb's potent infrared detectors with a wide mosaic view of the region's numerous sites of lensing.

According to astronomer Rachel Bezanson of the University of Pittsburgh in Pennsylvania, co-principal investigator on the "Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization" (UNCOVER) program to investigate the early universe, "The ancient myth of Pandora is about human curiosity and discoveries that delineate the past from the future, which I think is a fitting connection to the new realms of the universe Webb is opening up, including this deep-field image of Pandora’s Cluster," Rachel said.

“When the images of Pandora’s Cluster first came in from Webb, we were honestly a little star struck,” said Bezanson. “There was so much detail in the foreground cluster and so many distant lensed galaxies, I found myself getting lost in the image. Webb exceeded our expectations.” The new view of Pandora’s Cluster stitches four Webb snapshots together into one panoramic image, displaying roughly 50,000 sources of near-infrared light.

The appearance of distant galaxies is altered by gravitational lensing in addition to magnification, making them appear considerably different from those in the foreground. The "lens" created by the galaxy cluster is so large that it warps the very fabric of space, causing light from distant galaxies to seem twisted as it passes across the warped space.

Co-principal investigator on the UNCOVER program and astronomer Ivo Labbe of Swinburne University of Technology in Melbourne, Australia, said that the Webb telescope revealed hundreds of far-off lensed galaxies that appear as faint arcs in the image in the lensing core to the lower right of the Webb image. This region has never been imaged by Hubble. More of them become visible as you enlarge the area.

The cluster was photographed by the UNCOVER team using Webb's Near-Infrared Camera (NIRCam) over the course of around 30 hours of viewing time, with exposures lasting 4-6 hours each. The next step is to carefully review the imaging data and choose galaxies for follow-up observation with the Near-Infrared Spectrograph (NIRSpec), which will provide accurate distance measurements along with other comprehensive information about the compositions of the lensed galaxies, providing new insights into the early stage of galaxy assembly and evolution. These NIRSpec observations should be made in the summer of 2023, according to the UNCOVER team.

All of the NIRCam photometric data has been made available to the public in the interim, allowing other astronomers to familiarize themselves with it and design their own research projects using Webb's extensive databases. UNCOVER co-investigator Gabriel Brammer of the Cosmic Dawn Center at the University of Copenhagen remarked, "We are committed to assisting the astronomy community in making the best use of the amazing resource we have in Webb. This is just the beginning of all the amazing Webb science to come.”

Source - NASA