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When astronomers combine the observational powers of the James Webb Space Telescope and the Hubble Space Telescope, they are capturing more detailed images of the universe.
The new image showing a pair of galaxies, shared by NASA on Wednesday, is the startling result of using data from both space observatories.
Both telescopes contributed observations across different wavelengths of light. Webb can detect infrared light, which is invisible to the human eye, while Hubble has the ability to observe the two galaxies in visible light as well as ultraviolet light. The duo of an elliptical galaxy and a spiral galaxy is known as VV 191, It is located 700 million light years from Earth.
“We got more than we expected by combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope!” Webb wrote an interdisciplinary scientist and Regent Professor at Arizona State University Roger Windhurst NASA weblog.
“Webb’s new data allowed us to trace the light emitted from the bright white elliptical galaxy, on the left, through the spiral galaxy on the right — and determine the effects of interstellar dust in the spiral galaxy. … Webb’s near-infrared data also shows us the spiral arms. The taller and very dusty galaxy is in much more detail, giving the arms an overlapping appearance with the central bulge of the bright white elliptical galaxy on the left.”
The image is an early result of the so-called monitoring program Key extragalactic regions for reionization and lens science, or PEARLS, by Webb Telescope, which has not yet undergone a peer-review process. The study has been submitted to the Astrophysical Journal.
Scientists chose the galactic pair from nearly 2,000 candidates identified by science volunteers who are citizens of the Galaxy Zoo. These tiny galaxies, which appear very close together, don’t actually interact with each other, but they do allow researchers to track and compare galactic dust.
“It is important to understand where the dust is in galaxies, because dust changes the brightness and colors that appear in images of galaxies,” Windhurst wrote. “Dust grains are partly responsible for the formation of new stars and planets, so we always strive to determine their presence for further studies.”
But a closer look at this galactic pair isn’t the only celestial marvel revealed in this composite image. Other galaxies also appear behind the pair, and one of these points of light led to a second discovery within the new image. This phenomenon, called gravitational lensing, occurs when foreground galaxies act as a magnifying lens for the objects behind them.
Scientists used the same technique for Webb’s first photo was released in July. According to NASA, the space telescope “provided the deepest and most accurate infrared image of the distant universe to date.”
Above the white elliptical galaxy to the left is a faint red arc, and it is actually a very distant galaxy. The gravity of the elliptical galaxy in the foreground bends the light of the outermost galaxy. The warp also causes the distant galaxy to reappear as a red dot in the lower right of the elliptical galaxy.
Images of the distant galaxy are too faint to be recognized in the Hubble data, but they are clearly visible in Webb’s near-infrared observation.
“Simulations of gravitational lensing galaxies like this help us reconstruct the amount of mass in individual stars, along with how much dark matter is in the core of this galaxy,” Windhurst wrote.
He added that in addition to the insights astronomers are receiving about VV 191, this background to Webb’s image hints at more deeper mysteries in the universe yet to be revealed. “Two incomplete spirals in the upper left of the elliptical galaxy have similar apparent sizes, but appear very different colours. One is likely to be very dusty and the other very far away, but we – or other astronomers – need to get the data known as spectra to determine which is which .”