A new image from the James Webb Space Telescope shows thousands of glittering galaxies that it spied by peering through clouds of dust and using its infrared instruments to reveal what lies beneath. In the center of the image is the Spiderweb protocluster, which is a group of galaxies in the early stages of forming a “cosmic city.”
The light from the Spiderweb has been traveling for an astonishing 10 billion years to reach us, so looking at it is like looking back in time to the early stages of the universe. Astronomers are interested in studying this cluster of over 100 galaxies interacting together because it shows how galaxies clumped together to form groups when the universe was still young.
“We are observing the buildup of one the largest structures in the universe, a city of galaxies in construction,” explained researcher Jose M. Pérez-Martínez of the Institute of Astrophysics of the Canary Islands and the University of La Laguna in Spain. “We know that most galaxies in local galaxy clusters (the biggest metropolises of the universe) are old and not very active, whereas in this work, we are looking at these objects during their adolescence. As this city in construction grows, their physical properties will also be affected. Now, Webb is giving us new insights into the buildup of such structures for the first time.”
This annotated version of the Webb image highlights the galaxies that make up the Spiderweb group. Though there are many galaxies highlighted by the white circles, only a relatively small number of these are within the circle in the center, which indicates those that are bound together by gravity. When Webb looked through the dust at this region, it spotted many more galaxies in this protocluster than the researchers had anticipated.
“As expected, we found new galaxy cluster members, but we were surprised to find more than expected,” explained Rhythm Shimakawa of Waseda University in Japan. “We found that previously known galaxy members (similar to the typical star-forming galaxies like our Milky Way galaxy) are not as obscured or dust-filled as previously expected, which also came as a surprise.”
Webb is revealing all sorts of new information about the early universe, as it is the most powerful telescope currently available and can look at extremely distant objects — allowing it to see the early stages of the universe. Researchers have been surprised to find that the early universe is much busier and brighter than they had expected, suggesting that stars may have been forming faster than predicted.
In the case of the Spiderweb protocluster, the researchers think that the lower amounts of dust seen in these galaxies may be to do with the way these galaxies form and grow. Unlike the galaxies we see close to use today, in which star formation is often driven by galaxies interacting or merging with each other, there seems to be plentiful gas in the region from which stars are forming in this case.
The research is published in two papers in The Astronomical Journal.
