The James Webb Space Telescope’s spectacular view of the deep infrared universe has revealed 42 new, lensed images of galaxies, revealing the shape of the lens that could help us see the first galaxies before at unprecedented depth.
revelation James Webb Space Telescope deep field image, by US President Joe Biden White House event Held on July 11, it was a closely guarded secret. Teams of astronomers competed to be the first to analyze the image, with three new papers sent to the community’s preprint server within a week of publication.
“Honestly, we got a little burned!” Brenda Frye, an astronomer at the Steward Observatory at the University of Arizona and co-author of one of the papers, told Space.com. “We normally have a year or two warning but no one saw it” [this release] He’s coming at this hour.”
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this galaxy Cluster SMACS J0723.3-7327, known for short as SMACS J0723, is among a series of galaxy clusters that Webb has imaged for various gravitational lensing studies. Beyond that, Frye said, there has been nothing exceptional about the SMACS J0723 so far.
“Well chosen [to be one of the first images] because it was a relatively unknown target,” he said.
gravitational lensing is a phenomenon where the gravity of a very large object bends space into a shape similar to an optical lens, causing light from everything behind the lens to be distorted and magnified in brightness. Galaxy clusters are particularly efficient lenses because they pack enormous amounts of mass (in the case of SMACS J0723, about 100 trillion times the mass of the sun) into a relatively compact volume about 3 to 5 million light-years in diameter. .
previous surveys by Hubble space telescope and retired Herschel Space Observatory SMACS found a handful of lensed images of background galaxies in its J0723 observations. But Webb takes the hunt to a whole new level.
Led by Massimo Pascale, a graduate student at the University of California at Berkeley, Frye’s team discovered 42 new lensed images in the background of the new deep-field image. Gravity lenses can create multiple images of the same galaxy, so these 42 images represent 19 separate galaxies. Another team, led by Gabriel Caminha of the Max Planck Institute for Astrophysics in Germany, counted 27 new lensed images.
Regardless of the final number, these lensed images show scientists’ results in both visible and dark — SMACS is deployed in the J0723 cluster and in turn models the shape of the lens. One of the new papers by a team led by Guillaume Mahler of Durham University concluded that most of the mass is concentrated in the brightest, largest galaxy in the cluster.
“Our models not only describe mass, but we can also use it to describe the magnification of images with this lens,” Pascale told Space.com.
The current furthest confirmed galaxy is a distant object known as GN-z11It has a redshift of 11.09, so we see it as it existed 13.4 billion years ago, only 400 million years later. Big Bang. (“Redshift” refers to the lengthening of the wavelength of light produced as the universe expands between a distant object and the viewer. The higher the redshift factor, the farther away the light source is.)
An even more distant candidate HD1Discovered by the redshift of 13, it looks to us as it was just 300 million years after the Big Bang. Even more recently, Early results from Webb they identified another candidate galaxy at redshift 13, called GLASS-z11. However, astronomers have yet to confirm the redshifts of HD1 or GLASS-z11.
Webb is expected to break both of these redshift records, although it has yet to be determined whether any of the lensed galaxies seen in SMACS J0723 are further away than Gn-z11 or HD1. Pascale and Frye are interested in mapping a phenomenon called the “critical curve,” because it is along these curves that the gravitational lens exerts its greatest magnification and where astronomers have the best chance of seeing it. first galaxies.
“The typical magnification in a lens cluster is about a factor of 10, and that’s not enough to see the first galaxies,” Frye said. Said. “But if we look at the critical curve, that’s where things get magnified hundreds or even thousands of times.”
Think of a critical curve as contour lines on a topographic map of the surface. Soil. The more such contour lines are grouped together, the greater the height of any point on the surface. Similarly, a critical curve is where the contour lines of the gravitational potential come together, and the more they cluster, the stronger that potential and its accompanying magnification. The position and shape of lensed images can give an indication of where the critical curve is.
“Ultimately, what we want to do is look along the critical curve where the magnification is highest, and that’s where we’ll find the highest redshift galaxies,” Frye said. Said.
Thus, the first three papers in the Webb deep field focus on modeling the amount and distribution of matter in the foreground cluster, and ultimately the shape of the lens and the position of the critical curve.
However, modeling can also tell us about the galaxy cluster’s own history.
“We found that the mass distribution was slightly longer than expected,” Pascale said. “Maybe this merger history of the clusterand we can infer from that and learn something about cluster formation as a whole, which takes place in a very chaotic environment. Gravity All these galaxies attract each other.”
The next step for Pascale and Frye’s team and the authors of the other two papers is to go through the peer-review process to see these results published in scientific journals. Beyond that, data from Webb’s NIRISS (Near Infrared Imager and Slitless Spectrograph) await analysis and should help scientists determine the spectroscopic redshifts of lensed galaxies and see how far away they are. (The deep field image was taken by the Near Infrared Camera, NIRCam.)
“Before Webb screened it, SMACS J0723 wasn’t the star of the show,” Pascale said. “Now all of a sudden there’s paper upon paper describing how powerful Webb really is to reveal things we couldn’t see before.”
A preprint of Pascale and Frye’s paper can be found the game. Two other papers available the game and the game.
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