NASA’s James Webb Space Telescope has produced the sharpest, deepest infrared image of the distant universe to date. Webb’s first deep field is the galaxy cluster SMACS 0723 and it is packed with thousands of galaxies, including the faintest objects ever observed in the infrared.
Webb’s image encompasses a minuscule portion of the vast universe, which would appear the size of a grain of sand held at arm’s length to someone observing from the ground. The combined mass of this galaxy cluster acts as a gravitational lens, magnifying more distant galaxies, including some that appeared when the universe was less than a billion years old. This deep field, taken with Webb’s Near Infrared Camera (NIRCam), is a composite image made up of images at different wavelengths, totaling 12.5 hours of exposure—reaching depths in infrared wavelengths beyond the deepest fields of the Hubble Space Telescope, which took weeks. And this is just the beginning. Researchers will continue to use the Webb to take longer exposures, revealing more of our vast universe.
This image shows the galaxy cluster SMACS 0723 as it looked 4.6 billion years ago, with many more galaxies in front of and behind the cluster. As researchers begin to dig into the Webb data, much more information regarding this cluster will be revealed. This field was also imaged by the Mid-Infrared Instrument (MIRI), which observes light in the mid-infrared.
Webb’s NIRCam has brought distant galaxies into sharp focus: they have tiny, faint structures that have never been observed before, including star clusters and diffuse features.
The light from these galaxies took billions of years to reach us. When we look at the youngest galaxies in this field, we are looking back to less than a billion years following the Big Bang. The light was stretched by the expanding universe to infrared wavelengths that Webb is designed to observe. The scientific community will soon begin to learn more regarding the mass, age, history, and composition of these galaxies.
Other features include the prominent curvatures of this field. The powerful gravitational field of a galaxy cluster can bend light rays from the more distant galaxies behind it, much as a magnifying glass bends and distorts images. The stars were also captured with outstanding diffraction peaks, while appearing brighter at shorter wavelengths.
The image taken by Webb’s MIRI instrument offers a kaleidoscope of colors and highlights the places where there is dust, an important ingredient for the formation of stars and, ultimately, for life itself. Blue galaxies contain stars, but very little dust. Red objects in this field are enveloped in thick layers of dust. Green galaxies are populated with hydrocarbons and other chemical compounds. Researchers will be able to use data like this to understand how galaxies form, grow and merge, and why in some cases they stop creating stars altogether.
In addition to taking images, two of Webb’s instruments also obtained spectra, which is data that reveals the physical and chemical properties of objects and will help researchers identify much more detail regarding distant galaxies in this field. The Near-Infrared Spectrograph (NIRSpec) microshutter array observed 48 individual galaxies at the same time—a new technology used for the first time in space—sending back a full package of details regarding each one. The data revealed light from a galaxy that traveled for 13.1 billion years before Webb’s mirrors picked it up. The NIRSpec data also showed how detailed the spectra of the galaxies will be with Webb’s observations.
Finally, the Near Infrared Imager and Slitless Spectrograph (NIRISS) used its wide-field slitless spectroscopy to capture spectra of all objects in the entire field of view at once. Among the results, this shows that one of the galaxies has a mirror image, or mirror image.
SMACS 0723 can be seen near the constellation of Volans, the Flying Fish, in the southern hemisphere sky.
The James Webb Space Telescope is the world’s premier space science observatory. Webb will solve the mysteries of our solar system, see beyond distant worlds around other stars, and explore the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners: the European Space Agency and the Canadian Space Agency.
NASA headquarters oversees the mission for the agency’s Science Mission Directorate. NASA’s Goddard Space Flight Center in Greenbelt, Maryland manages Webb for the agency and oversees work on the mission by the Space Telescope Science Institute, Northrop Grumman and other mission partners. In addition to the Goddard Center, several NASA centers contributed to the project, including the agency’s Johnson Space Center in Houston, the Jet Propulsion Laboratory in southern California, the Marshall Space Flight Center in Huntsville, Alabama, and the Ames Research Center in Silicon Valley, California, among others.
NIRCam was built by a team from the University of Arizona and Lockheed Martin’s Center for Advanced Technology.
MIRI was contributed by the European Space Agency and NASA, and its instrument was designed and built by a nationally funded consortium of European Institutes (the European MIRI Consortium) in association with the Jet Propulsion Laboratory and the University of Arizona. .
NIRIS was contributed by the Canadian Space Agency. This instrument was designed and built by Honeywell in collaboration with the University of Montreal and the National Research Council of Canada.
NIRSpec was built for the European Space Agency by a consortium of European companies led by Airbus Defense and Space (ADS), with Goddard Space Flight Center providing its detector and microshutter subsystems.
For a complete set of early Webb images and spectra, including downloadable files, please visit:
https://webbtelescope.org/news/first-images
Credits: NASA, ESA, CSA and STScI.
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