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When astronomers combine the observing powers of the James Webb Space Telescope and the Hubble Space Telescope, they capture more detailed portraits of the cosmos.
A new image showing a galactic pair, shared by NASA on Wednesday, is the surprising result of using data from both space observatories.
Each telescope contributed observations through different wavelengths of light. Webb can detect infrared light, which is invisible to the human eye, while Hubble has the ability to view the two galaxies in visible light and ultraviolet light. The duo of elliptical galaxy and spiral galaxy is known as VV 191, and is located about 700 million light years from Earth.
“We got more than we bargained for by combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope!” wrote Webb interdisciplinary scientist and Regents Professor at Arizona State University Roger Windhorst by NASA Webb Blog.
“The new data from Webb allowed us to trace the light emitted by the bright white elliptical galaxy, on the left, through the winding spiral galaxy on the right, and to identify the effects of interstellar dust on the spiral galaxy. … The data from the Webb’s near infrared also shows us the galaxy’s longest and extremely dusty spiral arms in much greater detail, giving the arms an appearance of overlapping with the central bulge of the bright white elliptical galaxy on the left.”
The image is an early result of the observing program called Major extragalactic areas for reionization and lens science, or PEARLS, via the Webb Telescope, which has not yet gone through the peer review process. The study has been submitted to The Astrophysical Journal.
Scientists selected the galactic pair from nearly 2,000 candidates identified by Galaxy Zoo citizen scientist volunteers. These small galaxies, which appear close together, don’t actually interact with each other, but they allow researchers to track and compare galactic dust.
“It is important to understand where dust is present in galaxies, because dust changes the brightness and colors that appear in images of galaxies,” Windhorst wrote. “Dust grains are partially responsible for the formation of new stars and planets, so we are always looking to identify their presence for further study.”
But a closer look at this galactic pair isn’t the only celestial wonder this composite image revealed. Other galaxies are also visible 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 like a magnifying glass for objects behind them.
The scientists used the same technique to Webb’s first image released in July. The space telescope “delivered the deepest, sharpest infrared image of the distant universe to date,” according to NASA.
Above the white elliptical galaxy on the left is a faint red arc, which is actually a very distant galaxy. The gravity of the elliptical galaxy in the foreground has deflected the light from the more distant galaxy. The distant galaxy’s warping also causes it to reappear as a red dot in the lower right corner of the elliptical galaxy.
The images of the distant galaxy are so faint that they were not recognized in the Hubble data, but they show up clearly in Webb’s near-infrared observation.
“Gravitationally lensed galaxy simulations like this one help us piece together how much mass is in individual stars, along with how much dark matter is in the core of this galaxy,” Windhorst wrote.
Beyond the insights astronomers are gaining about VV 191, the background of this Webb image hints at deeper mysteries in the universe yet to be revealed, he added. “Two irregular spirals in the upper left of the elliptical galaxy have similar apparent sizes, but show up in very different colors. One is likely to be very dusty and the other very far away, but we, or other astronomers, need to obtain data known as spectra to determine which is which.”
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