The James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) has four observing modes. On Aug. 24, a mechanism that supports one of these modes, known as medium-resolution spectroscopy (MRS), exhibited what appears to be increased friction during setup for a science observation. This mechanism is a grating wheel that allows scientists to select between short, medium, and longer wavelengths when making observations using the MRS mode. Following preliminary health checks and investigations into the issue, an anomaly review board was convened Sept. 6 to assess the best path forward.
The Webb team has paused in scheduling observations using this particular observing mode while they continue to analyze its behavior and are currently developing strategies to resume MRS observations as soon as possible. The observatory is in good health, and MIRI’s other three observing modes – imaging, low-resolution spectroscopy, and coronagraphy – are operating normally and remain available for science observations.
Editor’s Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process.
NASA’s James Webb Space Telescope captured its first images and spectra of Mars Sept. 5. The telescope, an international collaboration with ESA (European Space Agency) and CSA (Canadian Space Agency), provides a unique perspective with its infrared sensitivity on our neighboring planet, complementing data being collected by orbiters, rovers, and other telescopes.
Webb’s unique observation post nearly a million miles away at the Sun-Earth Lagrange point 2 (L2) provides a view of Mars’ observable disk (the portion of the sunlit side that is facing the telescope). As a result, Webb can capture images and spectra with the spectral resolution needed to study short-term phenomena like dust storms, weather patterns, seasonal changes, and, in a single observation, processes that occur at different times (daytime, sunset, and nighttime) of a Martian day.
Because it is so close, the Red Planet is one of the brightest objects in the night sky in terms of both visible light (which human eyes can see) and the infrared light that Webb is designed to detect. This poses special challenges to the observatory, which was built to detect the extremely faint light of the most distant galaxies in the universe. Webb’s instruments are so sensitive that without special observing techniques, the bright infrared light from Mars is blinding, causing a phenomenon known as “detector saturation.” Astronomers adjusted for Mars’ extreme brightness by using very short exposures, measuring only some of the light that hit the detectors, and applying special data analysis techniques.
Webb’s first images of Mars, captured by the Near-Infrared Camera (NIRCam), show a region of the planet’s eastern hemisphere at two different wavelengths, or colors of infrared light. This image shows a surface reference map from NASA and the Mars Orbiter Laser Altimeter (MOLA) on the left, with the two Webb NIRCam instrument field of views overlaid. The near-infrared images from Webb are on shown on the right.
The NIRCam shorter-wavelength (2.1 microns) image [top right] is dominated by reflected sunlight, and thus reveals surface details similar to those apparent in visible-light images [left]. The rings of the Huygens Crater, the dark volcanic rock of Syrtis Major, and brightening in the Hellas Basin are all apparent in this image.
The NIRCam longer-wavelength (4.3 microns) image [lower right] shows thermal emission – light given off by the planet as it loses heat. The brightness of 4.3-micron light is related to the temperature of the surface and the atmosphere. The brightest region on the planet is where the Sun is nearly overhead, because it is generally warmest. The brightness decreases toward the polar regions, which receive less sunlight, and less light is emitted from the cooler northern hemisphere, which is experiencing winter at this time of year.
However, temperature is not the only factor affecting the amount of 4.3-micron light reaching Webb with this filter. As light emitted by the planet passes through Mars’ atmosphere, some gets absorbed by carbon dioxide (CO2) molecules. The Hellas Basin – which is the largest well-preserved impact structure on Mars, spanning more than 1,200 miles (2,000 kilometers) – appears darker than the surroundings because of this effect.
“This is actually not a thermal effect at Hellas,” explained the principal investigator, Geronimo Villanueva of NASA’s Goddard Space Flight Center, who designed these Webb observations. “The Hellas Basin is a lower altitude, and thus experiences higher air pressure. That higher pressure leads to a suppression of the thermal emission at this particular wavelength range [4.1-4.4 microns] due to an effect called pressure broadening. It will be very interesting to tease apart these competing effects in these data.”
Villanueva and his team also released Webb’s first near-infrared spectrum of Mars, demonstrating Webb’s power to study the Red Planet with spectroscopy.
Whereas the images show differences in brightness integrated over a large number of wavelengths from place to place across the planet at a particular day and time, the spectrum shows the subtle variations in brightness between hundreds of different wavelengths representative of the planet as a whole. Astronomers will analyze the features of the spectrum to gather additional information about the surface and atmosphere of the planet.
This infrared spectrum was obtained by combining measurements from all six of the high-resolution spectroscopy modes of Webb’s Near-Infrared Spectrograph (NIRSpec). Preliminary analysis of the spectrum shows a rich set of spectral features that contain information about dust, icy clouds, what kind of rocks are on the planet’s surface, and the composition of the atmosphere. The spectral signatures – including deep valleys known as absorption features – of water, carbon dioxide, and carbon monoxide are easily detected with Webb. The researchers have been analyzing the spectral data from these observations and are preparing a paper they will submit to a scientific journal for peer review and publication.
In the future, the Mars team will be using this imaging and spectroscopic data to explore regional differences across the planet, and to search for trace gases in the atmosphere, including methane and hydrogen chloride.
Right now, NASA’s James Webb Space Telescope is in space capturing spectacular images and spectrum of the universe; all of these data reside in the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute (STScI), the science operations center for Webb. However, it takes time for these exciting new observations to make their way from raw data to published, peer-reviewed science.
Scientific peer review is a long-established, quality-control system, where new scientific discoveries are scrutinized by experts before they are published in a journal. The peer review process begins when a scientist or group of scientists completes a study of a particular object in the sky and then submits their written findings to an accredited journal for publication. The journal’s editors will then circulate the article to other scientists within the same field to gather their reviews and feedback. Only articles that meet good scientific standards, acknowledging and building upon other known works, make it through this process and are published in the journal. NASA relies on this peer-review process to ensure quality and accuracy of scientific results before sharing them with the public.
Since Webb’s discoveries are so new, they require time to be vetted by the peer-review process, and a pipeline of articles under peer review is growing as the telescope continues to make observations from its first year of planned science. This pipeline of articles will feed future Webb news as scientists with peer-reviewed articles submit their findings to the STScI news office for consideration for promotion.
Many Webb investigators, however, are also taking advantage of the way that the scientific publication landscape has changed in the last decade. They create draft papers that are sometimes publicly posted as “preprints” before the full peer-review process is complete. This previewing stage allows for discussion within the science community, and researchers sometimes use this feedback to improve their written papers before they formally submit to a journal. At this stage, papers, imagery, figures, and initial analyses are public – but not yet considered part of the fully peer-reviewed scientific literature.
NASA and STScI, in collaboration with the science community, may share some imagery or spectra from papers prior to peer review, much like the recently published exoplanet images, as well as images from Webb data publicly available in the MAST archive. Those shared, but still awaiting peer review, will be labeled appropriately to describe where in the process the image or data and results are. Important scientific conclusions and discoveries from these images will be shared later, after peer review.
What to Expect
Starting the week of Sep. 19, NASA will share a new Webb image or spectrum at least every other week. Check the Webb blog every other Monday to find out when to expect that week’s image.
NASA will also hold media availability calls with subject matter experts as needed to answer questions about the latest images, spectra, and science from Webb.
-Thaddeus Cesari, NASA’s Goddard Space Flight Center
Editor’s Note: This post highlights images from Webb science in progress, which has not yet been through the peer-review process.
For the first time, astronomers have used NASA’s James Webb Space Telescope to take a direct image of a planet outside our solar system. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable.
The image, as seen through four different light filters, shows how Webb’s powerful infrared gaze can easily capture worlds beyond our solar system, pointing the way to future observations that will reveal more information than ever before about exoplanets.
“This is a transformative moment, not only for Webb but also for astronomy generally,” said Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter in the United Kingdom, who led these observations with a large international collaboration. Webb is an international mission led by NASA in collaboration with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
The exoplanet in Webb’s image, called HIP 65426 b, is about six to 12 times the mass of Jupiter, and these observations could help narrow that down even further. It is young as planets go — about 15 to 20 million years old, compared to our 4.5-billion-year-old Earth.
Astronomers discovered the planet in 2017 using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope in Chile and took images of it using short infrared wavelengths of light. Webb’s view, at longer infrared wavelengths, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth’s atmosphere.
Researchers have been analyzing the data from these observations and are preparing a paper they will submit to journals for peer review. But Webb’s first capture of an exoplanet already hints at future possibilities for studying distant worlds.
Since HIP 65426 b is about 100 times farther from its host star than Earth is from the Sun, it is sufficiently distant from the star that Webb can easily separate the planet from the star in the image.
Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are both equipped with coronagraphs, which are sets of tiny masks that block out starlight, enabling Webb to take direct images of certain exoplanets like this one. NASA’s Nancy Grace Roman Space Telescope, slated to launch later this decade, will demonstrate an even more advanced coronagraph.
“It was really impressive how well the Webb coronagraphs worked to suppress the light of the host star,” Hinkley said.
Taking direct images of exoplanets is challenging because stars are so much brighter than planets. The HIP 65426 b planet is more than 10,000 times fainter than its host star in the near-infrared, and a few thousand times fainter in the mid-infrared.
In each filter image, the planet appears as a slightly differently shaped blob of light. That is because of the particulars of Webb’s optical system and how it translates light through the different optics.
“Obtaining this image felt like digging for space treasure,” said Aarynn Carter, a postdoctoral researcher at the University of California, Santa Cruz, who led the analysis of the images. “At first all I could see was light from the star, but with careful image processing I was able to remove that light and uncover the planet.”
While this is not the first direct image of an exoplanet taken from space – the Hubble Space Telescope has captured direct exoplanet images previously – HIP 65426 b points the way forward for Webb’s exoplanet exploration.
“I think what’s most exciting is that we’ve only just begun,” Carter said. “There are many more images of exoplanets to come that will shape our overall understanding of their physics, chemistry, and formation. We may even discover previously unknown planets, too.”
With giant storms, powerful winds, auroras, and extreme temperature and pressure conditions, Jupiter has a lot going on. Now, NASA’s James Webb Space Telescope has captured new images of the planet. Webb’s Jupiter observations will give scientists even more clues to Jupiter’s inner life.
“We hadn’t really expected it to be this good, to be honest,” said planetary astronomer Imke de Pater, professor emerita of the University of California, Berkeley. De Pater led the observations of Jupiter with Thierry Fouchet, a professor at the Paris Observatory, as part of an international collaboration for Webb’s Early Release Science program. Webb itself is an international mission led by NASA with its partners ESA (European Space Agency) and CSA (Canadian Space Agency). “It’s really remarkable that we can see details on Jupiter together with its rings, tiny satellites, and even galaxies in one image,” she said.
The two images come from the observatory’s Near-Infrared Camera (NIRCam), which has three specialized infrared filters that showcase details of the planet. Since infrared light is invisible to the human eye, the light has been mapped onto the visible spectrum. Generally, the longest wavelengths appear redder and the shortest wavelengths are shown as more blue. Scientists collaborated with citizen scientist Judy Schmidt to translate the Webb data into images.
In the standalone view of Jupiter, created from a composite of several images from Webb, auroras extend to high altitudes above both the northern and southern poles of Jupiter. The auroras shine in a filter that is mapped to redder colors, which also highlights light reflected from lower clouds and upper hazes. A different filter, mapped to yellows and greens, shows hazes swirling around the northern and southern poles. A third filter, mapped to blues, showcases light that is reflected from a deeper main cloud.
The Great Red Spot, a famous storm so big it could swallow Earth, appears white in these views, as do other clouds, because they are reflecting a lot of sunlight.
“The brightness here indicates high altitude – so the Great Red Spot has high-altitude hazes, as does the equatorial region,” said Heidi Hammel, Webb interdisciplinary scientist for solar system observations and vice president for science at AURA. “The numerous bright white ‘spots’ and ‘streaks’ are likely very high-altitude cloud tops of condensed convective storms.” By contrast, dark ribbons north of the equatorial region have little cloud cover.
In a wide-field view, Webb sees Jupiter with its faint rings, which are a million times fainter than the planet, and two tiny moons called Amalthea and Adrastea. The fuzzy spots in the lower background are likely galaxies “photobombing” this Jovian view.
“This one image sums up the science of our Jupiter system program, which studies the dynamics and chemistry of Jupiter itself, its rings, and its satellite system,” Fouchet said. Researchers have already begun analyzing Webb data to get new science results about our solar system’s largest planet.
Data from telescopes like Webb doesn’t arrive on Earth neatly packaged. Instead, it contains information about the brightness of the light on Webb’s detectors. This information arrives at the Space Telescope Science Institute (STScI), Webb’s mission and science operations center, as raw data. STScI processes the data into calibrated files for scientific analysis and delivers it to the Mikulski Archive for Space Telescopes for dissemination. Scientists then translate that information into images like these during the course of their research (here’s a podcast about that). While a team at STScI formally processes Webb images for official release, non-professional astronomers known as citizen scientists often dive into the public data archive to retrieve and process images, too.
Judy Schmidt of Modesto California, a longtime image processor in the citizen science community, processed these new views of Jupiter. For the image that includes the tiny satellites, she collaborated with Ricardo Hueso, a co-investigator on these observations, who studies planetary atmospheres at the University of the Basque Country in Spain.
Schmidt has no formal educational background in astronomy. But 10 years ago, an ESA contest sparked her insatiable passion for image processing. The “Hubble’s Hidden Treasures” competition invited the public to find new gems in Hubble data. Out of nearly 3,000 submissions, Schmidt took home third place for an image of a newborn star.
Since the ESA contest, she has been working on Hubble and other telescope data as a hobby. “Something about it just stuck with me, and I can’t stop,” she said. “I could spend hours and hours every day.”
Her love of astronomy images led her to process images of nebulae, globular clusters, stellar nurseries, and more spectacular cosmic objects. Her guiding philosophy is: “I try to get it to look natural, even if it’s not anything close to what your eye can see.”These images have caught the attention of professional scientists, including Hammel, who previously collaborated with Schmidt on refining Hubble images of comet Shoemaker-Levy 9’s Jupiter impact.
Jupiter is actually harder to work with than more distant cosmic wonders, Schmidt says, because of how fast it rotates. Combining a stack of images into one view can be challenging when Jupiter’s distinctive features have rotated during the time that the images were taken and are no longer aligned. Sometimes she has to digitally make adjustments to stack the images in a way that makes sense.
Webb will deliver observations about every phase of cosmic history, but if Schmidt had to pick one thing to be excited about, it would be more Webb views of star-forming regions. In particular, she is fascinated by young stars that produce powerful jets in small nebula patches called Herbig–Haro objects. “I’m really looking forward to seeing these weird and wonderful baby stars blowing holes into nebulas,” she said.
Now that NASA’s James Webb Space Telescope’s first images and data are out, you might be wondering: What comes next?
The observatory has a packed schedule of science programs looking at all kinds of cosmic phenomena, like planets, stars, galaxies, black holes, and more. Webb will revolutionize our understanding of the universe — but first, researchers need time to analyze data and make sure that they understand what they’re seeing. Here are four things to know about Webb’s next steps:
More images are coming. Webb has already captured more images beyond the ones you saw on July 12, and the Cartwheel Galaxy is just one example. Hold onto your intergalactic hats — we’ll be rolling those out in the coming weeks at nasa.gov/webb and on the NASAWebb social media channels. Some of those images give a first look at Webb’s capabilities, but are not part of science programs. In the meantime, you can revisit the first images at nasa.gov/webbfirstimages. We also have this page where you can find the full array of images and data at full resolution.
News releases on results will be coming, too, once they have been reviewed. You may have seen scientists on social media posting their preliminary findings from Webb data. But before NASA publicizes results in news materials, we wait for the findings to be peer-reviewed — meaning, the science community has assessed the results. Science is a collaborative process of asking questions, testing out ideas, discussing with colleagues, and doing it all over. The peer-review process generally happens when researchers submit their findings to a journal or conference. It may take a little while, but it’s worth it.
The current Webb observing schedule is set and available. If you want to find out what Webb is looking at this week, visit the Space Telescope Science Institute’s weekly schedule to find out which cosmic objects the observatory is checking out. The full buffet of Webb observations for the next year, known as Cycle 1, is available here.
“It was worth the wait! Our immense golden telescope is seeing where none have seen before, discovering what we never knew before, and we are proud of what we have done. It’s our day to thank the people who made it possible, from the scientific visionaries in 1989 and 1995, to the 20,000 engineers, technicians, computer programmers, and scientists who did the work, and to the representatives of the people in the U.S., Europe, and Canada, who had faith in us and supported us. And special thanks to Senator Barbara Mikulski, who saved not one but two telescopes, with her inspiration and determination that setbacks are never the end. And special thanks to Goddard Project Manager Bill Ochs and Northrop Grumman Project Manager Scott Willoughby, who together pulled us all through every challenge to complete success.
“Already we have stood on the shoulders of giants like the Hubble and Spitzer space telescopes, and seen farther. We have seen distant galaxies, as they were when the universe was less than a billion years old, and we’re just beginning the search. We have seen galaxies colliding and merging, revealing their chemical secrets. We have seen one black hole close up, in the nucleus of a nearby galaxy, and measured the material escaping from it. We’ve seen the debris when a star exploded, liberating the chemical elements that will build the next generations of stars and planets. We have started a search for Earth 2.0, by watching a planet transiting in front of its star, and measuring the molecules in its atmosphere.
“What comes next? All the tools are working, better than we hoped and promised. Scientific observations, proposed years ago, are being made as we speak. We want to know: Where did we come from? What happened after the big bang to make galaxies and stars and black holes? We have predictions and guesses, but astronomy is an observational science, full of surprises. What are the dark matter and dark energy doing? How do stars and planets grow inside those beautiful clouds of gas and dust? Do the rocky planets we can observe with Webb have any atmosphere at all, and is there water there? Are there any planetary systems like our solar system? So far we have found exactly none. We’ll look at our own solar system with new infrared eyes, looking for chemical traces of our history, and tracking down mysteries like Jupiter’s Great Red Spot, composition of the ocean under the ice of Europa, and the atmosphere of Saturn’s giant moon Titan. We’ll be ready to study the next interstellar comet.
“With the precise launch on Christmas morning 2021, we look forward to 20 years of operation before we run out of propellant. Though we suffer the pings of tiny micrometeoroids, so tiny you couldn’t feel one if you had it in your fingers, we think the telescope can meet its original performance likely long beyond its five-year design life. In 2027 we will launch the Nancy Grace Roman Space Telescope, which will scan vast areas of the sky for new fascinating targets for Webb, while also hunting for the effects of dark matter and dark energy. We know the Webb images will rewrite our textbooks, and we hope for a new discovery, something so important that our view of the universe will be overturned once again.
Webb was worth the wait!”
– John Mather, Webb senior project scientist, NASA Goddard
On the heels of Tuesday’s release of the first images from NASA’s James Webb Space Telescope, data from the telescope’s commissioning period is now being released on the Space Telescope Science Institute’s Mikulski Archive for Space Telescopes. The data includes images of Jupiter and images and spectra of several asteroids, captured to test the telescope’s instruments before science operations officially began July 12. The data demonstrates Webb’s ability to track solar system targets and produce images and spectra with unprecedented detail.
Fans of Jupiter will recognize some familiar features of our solar system’s enormous planet in these images seen through Webb’s infrared gaze. A view from the NIRCam instrument’s short-wavelength filter shows distinct bands that encircle the planet as well as the Great Red Spot, a storm big enough to swallow the Earth. The iconic spot appears white in this image because of the way Webb’s infrared image was processed.
“Combined with the deep field images released the other day, these images of Jupiter demonstrate the full grasp of what Webb can observe, from the faintest, most distant observable galaxies to planets in our own cosmic backyard that you can see with the naked eye from your actual backyard,” said Bryan Holler, a scientist at the Space Telescope Science Institute in Baltimore, who helped plan these observations.
Clearly visible at left is Europa, a moon with a probable ocean below its thick icy crust, and the target of NASA’s forthcoming Europa Clipper mission. What’s more, Europa’s shadow can be seen to the left of the Great Red Spot. Other visible moons in these images include Thebe and Metis.
“I couldn’t believe that we saw everything so clearly, and how bright they were,” said Stefanie Milam, Webb’s deputy project scientist for planetary science based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s really exciting to think of the capability and opportunity that we have for observing these kinds of objects in our solar system.”
Scientists were especially eager to see these images because they are proof that Webb can observe the satellites and rings near bright solar system objects such as Jupiter, Saturn, and Mars. Scientists will use Webb to explore the tantalizing question of whether we can see plumes of material spewing out of moons like Europa and Saturn’s moon Enceladus. Webb may be able to see the signatures of plumes depositing material on the surface on Europa. “I think that’s just one of the coolest things that we’ll be able to do with this telescope in the solar system,” Milam said.
Additionally, Webb easily captured some of Jupiter’s rings, which especially stand out in the NIRcam long-wavelength filter image. That the rings showed up in one of Webb’s first solar system images is “absolutely astonishing and amazing,” Milam said.
“The Jupiter images in the narrow-band filters were designed to provide nice images of the entire disk of the planet, but the wealth of additional information about very faint objects (Metis, Thebe, the main ring, hazes) in those images with approximately one-minute exposures was absolutely a very pleasant surprise,” said John Stansberry, observatory scientist and NIRCam commissioning lead at the Space Telescope Science Institute.
Webb also obtained these images of Jupiter and Europa moving across the telescope’s field of view in three separate observations. This test demonstrated the ability of the observatory to find and track guide stars in the vicinity of bright Jupiter.
But just how fast can an object move and still be tracked by Webb? This was an important question for scientists who study asteroids and comets. During commissioning, Webb used an asteroid called 6481 Tenzing, located in the asteroid belt between Mars and Jupiter, to start the moving-target tracking “speed limit” tests.
Webb was designed with the requirement to track objects that move as fast as Mars, which has a maximum speed of 30 milliarcseconds per second. During commissioning, the Webb team conducted observations of various asteroids, which all appeared as a dot because they were all small. The team proved that Webb will still get valuable data with all of the science instruments for objects moving up to 67 milliarcseconds per second, which is more than twice the expected baseline – similar to photographing a turtle crawling when you’re standing a mile away. “Everything worked brilliantly,” Milam said.
Yesterday, NASA and its partners, ESA (European Space Agency) and CSA (Canadian Space Agency), released the full set of the first full-color images and spectroscopic data from the James Webb Space Telescope.
The images, which uncover a collection of cosmic features elusive until now, are available at: nasa.gov/webbfirstimages.
The months-long process of preparing NASA’s James Webb Space Telescope for science is now complete. All of the seventeen ways or ‘modes’ to operate Webb’s scientific instruments have now been checked out, which means that Webb has completed its commissioning activities and is ready to begin full scientific operations.
Each of Webb’s four scientific instruments has multiple modes of operation, utilizing customized lenses, filters, prisms, and specialized machinery that needed to be individually tested, calibrated, and ultimately verified in their operational configuration in space before beginning to capture precise scientific observations of the universe. The last of all seventeen instrument modes to be commissioned was NIRCam’s coronagraph capability, which works to mostly block incoming starlight by inserting a mask in front of a target star, suppressing the target star’s relatively bright light to increase contrast and enable detection of fainter nearby companions such as exoplanets. NIRCam, or the Near-Infrared Camera, is equipped with five coronagraphic masks — three round masks and two bar-shaped masks — that suppress starlight under different conditions of contrast and separation between the star and its companions.
In addition to capturing detailed imagery of the universe, NIRCam is the observatory’s main wavefront sensor that is used to fine-tune the telescope’s optics. It has this double duty by design due to having a comparatively wide field of view and possessing a suite of special internal optics that enable it to take out-of-focus images of stars and even take ‘selfie’ images of the primary mirror itself. The team was able to start aligning the telescope’s optics even while the observatory was still cooling down, because of NIRCam’s ability to safely operate at higher-than-normal, but still cryogenic, operating temperatures.
“From the moment we first took images with NIRCam to start the telescope alignment process to the checkout of coronagraphy at the end of commissioning, NIRCam has performed flawlessly. Observers are going to be very pleased with the data they receive, and I am extremely happy with how 20 years of work by my team are now realized in amazing performance,” said Marcia Rieke, principal investigator for the NIRCam instrument and regents professor of astronomy, University of Arizona.