Webb is producing the deepest and sharpest infrared (IR) images of the distant universe to date. This first image revealed, known as Webb’s First Deep Field, is of a galaxy cluster SMACS 0723 (see Fig. 1 in gallery above). It shows SMACS 0723 as it appeared 4.6 billion years ago, but perhaps the coolest aspect here is the combined mass of this galaxy cluster acting as a gravitational lens to magnify much more distant galaxies behind it.
This deep-field image shot by Webb’s Near-Infrared Camera (NIRCam), which was built by a team from the University of Arizona and Lockheed Martin, is a composite of images at different wavelengths.
It’s a “singular and historical moment,” says Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “It took decades of drive and perseverance to get us here, and I’m immensely proud of the Webb team. These first images show us how much we can accomplish when we come together behind a shared goal to solve the cosmic mysteries that connect us all. It’s a stunning glimpse into the insights yet to come.”
NIRCam
NIRCam is Webb’s primary imager and it operates over a wavelength range of 0.6 to 5 µm. It can detect light from the earliest stars and galaxies in the process of formation, the population of stars in nearby galaxies, as well as young stars withing the Milky Way and Kuiper objects.
NIRCam features 10 mercury-cadmium-telluride (HgCdTe) detector arrays, which are analogous to charge-coupled devices (CCDs) used in off-the-shelf digital cameras. It’s also an optical telescope element wavefront sensor, which helps bring distant galaxies into sharp focus—including their tiny, faint structures never been seen before, such as star clusters and diffuse features.
It's also equipped with coronagraphs to allow astronomers to take pictures of very faint objects around stellar systems. NIRCam’s coronagraphs work by blocking a brighter object’s light, making it possible to view the dimmer object nearby—akin to shielding your eyes from the sun by raising your hand to block it to focus on the view in front of you. With coronagraphs, astronomers hope to determine the characteristics of planets orbiting nearby stars.
An exoplanet’s atmosphere
Another Webb image released today shows the most detailed spectrum to date of the atmosphere of an exoplanet (WASP-96 b) more than 1000 light-years away (see Fig. 2 in gallery above). Webb’s 270-sq-ft. mirror, spectrographs, and sensitive detectors revealed the unambiguous signature of water, indications of haze, and evidence for clouds not thought to exist based on prior observations.
This observation reveals the presence of specific gas molecules based on tiny decreases in the brightness of precise colors of light, according to NASA, and is the most detailed of its kind to date—demonstrating Webb’s unprecedented ability to analyze atmospheres hundreds of light-years away.
A star is born in Carina Nebula
The landscape of mountains and valleys speckled with glittering stars shown in Figure 3 (see gallery above) is actually the edge of a nearby young star-forming region called NGC 3325 within the Carina Nebula. Captured in IR light by Webb, it’s revealing for the first time previously invisible areas of star birth.
Dubbed “Cosmic Cliffs,” Webb’s 3D-like picture appears to be craggy mountains on a moonlit evening, but it’s actually the edge of the giant, gaseous cavity within NGC 3324, and the tallest “peaks” are about 7 light-years high. The cavernous area was carved from the nebula by the intense ultraviolet radiation and stellar winds from extremely massive, hot, young stars within the center of the bubble, above the area shown in this image.
Webb reveals emerging stellar nurseries and individual stars completely hidden in visible light images, but its sensitivity to IR light allows it to peer through cosmic dust to see these objects. Protostellar jets are clearly seen shooting out of some of these young stars. The youngest sources appear as red dots in the dark, dusty region of the cloud.
This image was shot with Webb’s NIRCam and its Mid-Infrared Instrument (MIRI). The MIRI provides observers with coverage of mid-IR wavelengths from 4.9 to 28.8 µm, and imaging can be obtained with nine broadband filters covering wavelength ranges from 5.6 to 25.5 µm.
Spectroscopy can be obtained via a low spectral resolving power mode from 5 to 12 µm that includes both slitted and slitless options, or with a medium spectral resolving power integral field unit from 4.9 to 28.8 µm. MIRI also contains one Lyot and three 4-quadrant phase mask coronagraphs optimized to the mid-IR spectral region.
A star in final throes of death
Webb’s NIRCam and MIRI captured the details of the Southern Ring planetary nebula (see Fig. 4 in gallery above), which are shells of gas and dust ejected by dying stars, and were previously hidden from astronomers.
New details from the last stages of a star’s life can help researchers explore how stars evolve and transform their environments, and this image also reveals a cache of distant galaxies in the background (multicolored points of light shown in this image are galaxies, not stars).
Galaxy evolution and black holes
In one gigantic image, Webb reveals details about a galaxy group “Stephan’s Quintet,” (see Fig. 5 in gallery above) showing how interacting galaxies trigger star formation in each other and how gas within galaxies gets disturbed.
This image is Webb’s largest to date—covering about one-fifth of the Moon’s diameter. It’s made of 150 million pixels and constructed from almost 1000 separate image files, according to NASA, and provides new insights into how galactic interactions may have driven galaxy evolution in the early universe.
“Scientists are thrilled Webb is alive and as powerful as we hoped for, far beyond Hubble, and that it survived all hazards to be our golden eye in the sky,” says John Mather, senior project scientist at NASA’s Goddard Space Flight Center. “What happened after the Big Bang? How did the expanding universe cool down and make black holes, galaxies, stars, planets, and people? Astronomers see everything twice: first with pictures, and then with imagination and calculation. But there’s something out there that we’ve never imagined, and I will be as amazed as you are when we find it.”
Webb is an international program led by NASA, with partners the European Space Agency and the Canadian Space Agency.
Mysterious, rare ring galaxy
The Cartwheel Galaxy, a rare ring galaxy once shrouded in dust and mystery, has been unveiled by Webb’s imaging capabilities (see Fig. 6 in gallery above).
The galaxy, which formed as a result of a collision between a large spiral galaxy and another smaller galaxy, not only retained a lot of its spiral character, but has also experienced massive changes throughout its structure.
Webb’s high-precision instruments resolved individual stars and star-forming regions within the Cartwheel, and revealed the behavior of the black hole within its galactic center. These new details provide a renewed understanding of a galaxy in the midst of a slow transformation.
Stay tuned: More to come
NASA plans to release Webb images of Jupiter.
