At left, the quasar stands out in a Hubble image taken in visible and near-infrared light. The images to the right and bottom present new observations of the Webb at multiple wavelengths. – NASA, ESA, CSA, STSCI,
Oct. 20 () –
The James Webb Space Telescope has revealed the surprising discovery of a massive galaxy cluster in the process of forming around an extremely red quasar.
The result will further our understanding of how galaxy clusters in the early universe came together and formed the cosmic web we see today. according to NASA.
A quasar, a special type of active galactic nucleus (AGN), is a compact region with a supermassive black hole at the center of a galaxy. Gas falling into a supermassive black hole causes the quasar be bright enough to outshine all the stars in the galaxy.
The quasar that Webb explored, called SDSS J165202.64+172852.3, existed 11.5 billion years ago. It is unusually red not only because of its intrinsic red color, but also because the galaxy’s light has been redshifted due to its great distance. That made Webb, which has unparalleled sensitivity at infrared wavelengths, perfectly suited to examining the galaxy in detail.
This quasar is one of the most powerful galactic nuclei ever seen at such an extreme distance. Astronomers had speculated that the extreme emission from the quasar could cause a “galactic wind”, pushing free gas out of its host galaxy and possibly greatly influencing future star formation there.
To investigate the movement of gas, dust, and stellar material in the galaxy, the team used the telescope’s Near Infrared Spectrograph (NIRSpec). This powerful instrument uses a technique called spectroscopy to observe the movement of various flows and winds that surround the quasar. NIRSpec can collect spectra simultaneously across the telescope’s entire field of view, rather than just one point at a time, allowing Webb to simultaneously examine the quasar, its galaxy, and the wider surroundings.
Previous studies by the Hubble Space Telescope and other observatories had drawn attention to the quasar’s powerful outflows, and astronomers had speculated that its host galaxy might be merging with some unseen companion. But the team didn’t expect Webb’s NIRSpec data to clearly indicate that it wasn’t just one galaxy, but at least three others circling it. Thanks to the spectra in a wide area, the movements of all this surrounding material could be mapped, leading to the conclusion that the red quasar was, in fact, part of a dense knot of galaxy formation.
“There are few known galaxy protoclusters at this early time. They are hard to find and very few have had time to form since the Big Bang.said astronomer Dominika Wylezalek of the University of Heidelberg in Germany, who led the study with Webb. “This may eventually help us understand how galaxies evolve in dense environments. It’s an exciting result.”
Using the NIRSpec observations, the team was able to confirm three galactic companions of this quasar and show how they are connected. Archive data from Hubble hints that there may be even more. Images from Hubble’s Wide Field Camera 3 had shown extensive material surrounding the quasar and its galaxy, prompting its selection for this study on its output and effects on its host galaxy. Now, the team suspects they might have been looking at the core of an entire cluster of galaxies, only now Webb’s sharp images reveal it.
“Our first look at the data quickly revealed clear signs of important interactions between neighboring galaxies,” shared team member Andrey Vayner of Johns Hopkins University. “The sensitivity of the NIRSpec instrument was immediately apparent, And it was clear to me that we are in a new era of infrared spectroscopy.”
All three confirmed galaxies are orbiting each other at incredibly high speeds, an indication that a large amount of mass is present. When combined with how close they are to the region around this quasar, the team believe this marks one of the densest known areas of galaxy formation in the early universe.
“Even a dense knot of dark matter is not enough to explain it,” Wylezalek says. “We think we might be looking at a region where two massive halos of dark matter are merging.” Dark matter is an invisible component of the universe that holds galaxies and galaxy clusters together, and is thought to form a “halo” that extends beyond the stars in these structures.
These results will be published in The Astrophysical Journal Letters.
