Researchers could trace the light emitted from the largely white, elliptical galaxy on the left through the spiral galaxy on the right and determine the effects of interstellar dust in the spiral galaxy. This was done by combining data from the NASA/ESA/CSA James Webb Space Telescope and the NASA/ESA Hubble Space Telescope. Near-infrared light from Webb and ultraviolet and visible light from Hubble are combined to create this image of the galaxy pair VV 191.
The longer, extremely dusty spiral arms of the galaxy are also visible in much more detail in Webb’s near-infrared data, creating the impression that they overlap with the central bulge of the bright white, elliptical galaxy on the left. The two foreground galaxies are not actively interacting despite being quite close to one another from an astronomical perspective.
NASA’s officials said, “We got more than we bargained for by combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope! Webb’s new data allowed us to trace the light emitted by the bright white, elliptical galaxy, at left, through the winding spiral galaxy at right – and identify the effects of interstellar dust in the spiral galaxy. This image of galaxy pair VV 191 includes near-infrared light from Webb and ultraviolet and visible light from Hubble.”
“VV 191 is the latest addition to a small number of galaxies that helps researchers like us directly compare the properties of galactic dust. This target was selected from nearly 2,000 superimposed galaxy pairs identified by Galaxy Zoo citizen science volunteers.”
Because dust alters the brightness and color that appear in pictures of galaxies, it is crucial to understand where dust is present in galaxies. Researchers are actively searching for dust grains for future research because they play a role in forming new stars and planets.
A second discovery that is simpler to miss is contained in the image. Look at the elliptical white galaxy to the left. The inset shows a faint red arc at 10 o’clock. Due to the gravity of the elliptical foreground galaxy, the light from this very distant galaxy is bent, duplicating its appearance. Where the stretched red arc recurs at 4 o’clock as a dot, it is warped.
NASA noted, “These images of the lensed galaxy are so faint and so red that they went unrecognized in Hubble data but are unmistakable in Webb’s near-infrared image. Simulations of gravitationally lensed galaxies like this help us reconstruct how much mass is in individual stars and how much dark matter is in the core of this galaxy.”
“Like many Webb images, this image of VV 191 shows different galaxies deeper and deeper in the background. Two patchy spirals to the upper left of the elliptical galaxy have similar apparent sizes but show up in very different colors. One is likely 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.”