NASA's Webb, Hubble Combine to Create Most Colorful View of Universe

A field of galaxies on the black background of space. In the middle, stretching from left to right, is a collection of dozens of yellowish spiral and elliptical galaxies that form a foreground galaxy cluster. They form a rough, flat line along the center. Among them are distorted linear features, which mostly appear to follow invisible concentric circles curving around the center of the image. The linear features are created when the light of a background galaxy is bent and magnified through gravitational lensing. At center left, a particularly prominent example stretches vertically about three times the length of a nearby galaxy. A variety of brightly colored, red and blue galaxies of various shapes are scattered across the image, making it feel densely populated. Near the center are two tiny galaxies compared to the galaxy cluster: a very red edge-on spiral and a very blue face-on spiral, which provide a striking color contrast.

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from NASA’s James Webb Space Telescope with visible-light data from NASA’s Hubble Space Telescope. Credits: Image NASA, ESA, CSA, STScI, Jose M. Diego (IFCA), Jordan C. J. D’Silva (UWA), Anton M. Koekemoer (STScI), Jake Summers (ASU), Rogier Windhorst (ASU), Haojing Yan (University of Missouri)

NASA’s James Webb Space Telescope and Hubble Space Telescope have united to study an expansive galaxy cluster known as MACS0416. The resulting panchromatic image combines visible and infrared light to assemble one of the most comprehensive views of the universe ever taken. Located about 4.3 billion light-years from Earth, MACS0416 is a pair of colliding galaxy clusters that will eventually combine to form an even bigger cluster.

The image reveals a wealth of details that are only possible by combining the power of both space telescopes. It includes a bounty of galaxies outside the cluster and a sprinkling of sources that vary over time, likely due to gravitational lensing – the distortion and amplification of light from distant background sources.

This cluster was the first of a set of unprecedented, super-deep views of the universe from an ambitious, collaborative Hubble program called the Frontier Fields, inaugurated in 2014. Hubble pioneered the search for some of the intrinsically faintest and youngest galaxies ever detected. Webb’s infrared view significantly bolsters this deep look by going even farther into the early universe with its infrared vision.

“We are building on Hubble’s legacy by pushing to greater distances and fainter objects,” said Rogier Windhorst of Arizona State University, principal investigator of the PEARLS program (Prime Extragalactic Areas for Reionization and Lensing Science), which took the Webb observations.

What the Colors Mean

To make the image, in general the shortest wavelengths of light were color-coded blue, the longest wavelengths red, and intermediate wavelengths green. The broad range of wavelengths, from 0.4 to 5 microns, yields a particularly vivid landscape of galaxies.

Those colors give clues to galaxy distances: The bluest galaxies are relatively nearby and often show intense star formation, as best detected by Hubble, while the redder galaxies tend to be more distant as detected by Webb. Some galaxies also appear very red because they contain copious amounts of cosmic dust that tends to absorb bluer colors of starlight.

“The whole picture doesn’t become clear until you combine Webb data with Hubble data,” said Windhorst.