17.02.2023
NASA’s Webb Uncovers New Details in Pandora’s Cluster
Astronomers have revealed the latest deep field image from NASA’s James Webb Space Telescope, featuring never-before-seen details in a region of space known as Pandora’s Cluster (Abell 2744). Webb’s view displays three clusters of galaxies – already massive – coming together to form a megacluster. The combined mass of the galaxy clusters creates a powerful gravitational lens, a natural magnification effect of gravity, allowing much more distant galaxies in the early universe to be observed by using the cluster like a magnifying glass.
Only Pandora’s central core has previously been studied in detail by NASA’s Hubble Space Telescope. By combining Webb’s powerful infrared instruments with a broad mosaic view of the region’s multiple areas of lensing, astronomers aimed to achieve a balance of breadth and depth that will open up a new frontier in the study of cosmology and galaxy evolution.
“The ancient myth of Pandora is about human curiosity and discoveries that delineate the past from the future, which I think is a fitting connection to the new realms of the universe Webb is opening up, including this deep-field image of Pandora’s Cluster,” said astronomer Rachel Bezanson of the University of Pittsburgh in Pennsylvania, co-principal investigator on the “Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization” (UNCOVER) program to study the region.
“When the images of Pandora’s Cluster first came in from Webb, we were honestly a little star struck,” said Bezanson. “There was so much detail in the foreground cluster and so many distant lensed galaxies, I found myself getting lost in the image. Webb exceeded our expectations.” The new view of Pandora’s Cluster stitches four Webb snapshots together into one panoramic image, displaying roughly 50,000 sources of near-infrared light.
In addition to magnification, gravitational lensing distorts the appearance of distant galaxies, so they look very different than those in the foreground. The galaxy cluster “lens” is so massive that it warps the fabric of space itself, enough for light from distant galaxies that passes through that warped space to also take on a warped appearance.
Astronomer Ivo Labbe of the Swinburne University of Technology in Melbourne, Australia, co-principal investigator on the UNCOVER program, said that in the lensing core to the lower right in the Webb image, which has never been imaged by Hubble, Webb revealed hundreds of distant lensed galaxies that appear like faint arced lines in the image. Zooming in on the region reveals more and more of them.
“Pandora’s Cluster, as imaged by Webb, shows us a stronger, wider, deeper, better lens than we have ever seen before,” Labbe said. “My first reaction to the image was that it was so beautiful, it looked like a galaxy formation simulation. We had to remind ourselves that this was real data, and we are working in a new era of astronomy now.”
The UNCOVER team used Webb’s Near-Infrared Camera (NIRCam) to capture the cluster with exposures lasting 4-6 hours, for a total of about 30 hours of observing time. The next step is to meticulously go through the imaging data and select galaxies for follow-up observation with the Near-Infrared Spectrograph (NIRSpec), which will provide precise distance measurements, along with other detailed information about the lensed galaxies’ compositions, providing new insights into the early era of galaxy assembly and evolution. The UNCOVER team expects to make these NIRSpec observations in the summer of 2023.
In the meantime, all of the NIRCam photometric data has been publicly released so that other astronomers can become familiar with it and plan their own scientific studies with Webb’s rich datasets. “We are committed to helping the astronomy community make the best use of the fantastic resource we have in Webb,” said UNCOVER co-investigator Gabriel Brammer of the Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen. “This is just the beginning of all the amazing Webb science to come.”
The imaging mosaics and catalog of sources on Pandora’s Cluster (Abell 2744) provided by the UNCOVER team combine publicly available Hubble data with Webb photometry from three early observation programs: JWST-GO-2561, JWST-DD-ERS-1324, and JWST-DD-2756.
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
Quelle: NASA
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Update: 18.02.2023
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NASA’s Webb Reveals Intricate Networks of Gas and Dust in Nearby Galaxies
Researchers using NASA’s James Webb Space Telescope are getting their first look at star formation, gas, and dust in nearby galaxies with unprecedented resolution at infrared wavelengths. The data has enabled an initial collection of 21 research papers which provide new insight into how some of the smallest-scale processes in our universe – the beginnings of star formation – impact the evolution of the largest objects in our cosmos: galaxies.
The largest survey of nearby galaxies in Webb’s first year of science operations is being carried out by the Physics at High Angular resolution in Nearby Galaxies (PHANGS) collaboration, involving more than 100 researchers from around the globe. The Webb observations are led by Janice Lee, Gemini Observatory chief scientist at the National Science Foundation’s NOIRLab and affiliate astronomer at the University of Arizona in Tucson.
The team is studying a diverse sample of 19 spiral galaxies, and in Webb’s first few months of science operations, observations of five of those targets – M74, NGC 7496, IC 5332, NGC 1365, and NGC 1433 – have taken place. The results are already astounding astronomers.
“The clarity with which we are seeing the fine structure certainly caught us by surprise,” said team member David Thilker of Johns Hopkins University in Baltimore, Maryland.
“We are directly seeing how the energy from the formation of young stars affects the gas around them, and it’s just remarkable,” said team member Erik Rosolowsky of the University of Alberta, Canada.
The images from Webb’s Mid-Infrared Instrument (MIRI) reveal the presence of a network of highly structured features within these galaxies – glowing cavities of dust and huge cavernous bubbles of gas that line the spiral arms. In some regions of the nearby galaxies observed, this web of features appears built from both individual and overlapping shells and bubbles where young stars are releasing energy.
“Areas which are completely dark in Hubble imaging light up in exquisite detail in these new infrared images, allowing us to study how the dust in the interstellar medium has absorbed the light from forming stars and emitted it back out in the infrared, illuminating an intricate network of gas and dust,” said team member Karin Sandstrom of the University of California, San Diego.
The high-resolution imaging needed to study these structures has long evaded astronomers – until Webb came into the picture.
“The PHANGS team has spent years observing these galaxies at optical, radio, and ultraviolent wavelengths using NASA’s Hubble Space Telescope, the Atacama Large Millimeter/Submillimeter Array, and the Very Large Telescope’s Multi Unit Spectroscopic Explorer,” added team member Adam Leroy of the Ohio State University. “But, the earliest stages of a star’s lifecycle have remained out of view because the process is enshrouded within gas and dust clouds.”
Webb’s powerful infrared capabilities can pierce through the dust to connect the missing puzzle pieces.
For example, specific wavelengths observable by MIRI (7.7 and 11.3 microns) and Webb’s Near-Infrared Camera (3.3 microns) are sensitive to emission from polycyclic aromatic hydrocarbons, which play a critical role in the formation of stars and planets. These molecules were detected by Webb in the first observations by the PHANGS program.
Studying these interactions at the finest scale can help provide insights into the larger picture of how galaxies have evolved over time.
“Because these observations are taken as part of what's called a treasury program, they are available to the public as they are observed and received on Earth,” said Eva Schinnerer of the Max Planck Institute for Astronomy in Heidelberg, Germany, and leader of the PHANGS collaboration.
The PHANGS team will work to create and release data sets that align Webb’s data to each of the complementary data sets obtained previously from the other observatories, to help accelerate discovery by the broader astronomical community.
“Thanks to the telescope's resolution, for the first time we can conduct a complete census of star formation, and take inventories of the interstellar medium bubble structures in nearby galaxies beyond the Local Group,” Lee said. “That census will help us understand how star formation and its feedback imprint themselves on the interstellar medium, then give rise to the next generation of stars, or how it actually impedes the next generation of stars from being formed.”
The research by the PHANGS team is being conducted as part of General Observer program 2107. The team’s initial findings, comprised of 21 individual studies, were recently published in a special focus issue of The Astrophysical Journal Letters.
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency), and CSA (Canadian Space Agency).
Quelle: NASA
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Update: 24.02.2023
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James Webb telescope detects evidence of ancient ‘universe breaker’ galaxies
Huge systems appear to be far larger than was presumed possible so early after big bang, say scientists
The six candidate galaxies, based on observations by Nasa's James Webb space telescope.Photograph NASA
The James Webb space telescope has detected what appear to be six massive ancient galaxies, which astronomers are calling “universe breakers” because their existence could upend current theories of cosmology.
The objects date to a time when the universe was just 3% of its current age and are far larger than was presumed possible for galaxies so early after the big bang. If confirmed, the findings would call into question scientists’ understanding of how the earliest galaxies formed.
“These objects are way more massive than anyone expected,” said Joel Leja, an assistant professor of astronomy and astrophysics at Penn State University and a study co-author. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”
The observations come from the first dataset released from Nasa’s James Webb space telescope, which is equipped with infrared-sensing instruments capable of detecting light emitted by the most ancient stars and galaxies. While sifting through images, Dr Erica Nelson, of the University of Colorado Boulder, and a co-author, spotted a series of “fuzzy dots” that appeared unusually bright and unusually red.
Redness in astronomy is a proxy for age, because as light travels across the expanding universe it is stretched out, or red-shifted. These galaxies appeared to be roughly 13.5bn years old, placing them about 500m-700m years after the big bang.
These would not be the oldest galaxies observed by James Webb, which launched in December 2021. Last year, scientists spotted four galaxies that date to about 350m years after the big bang, but these were far smaller. Calculations suggest the latest galaxies harboured tens to hundreds of billions of sun-sized stars’ worth of mass, putting them on par with the Milky Way.
“It’s bananas,” said Nelson. “These galaxies should not have had time to form.”
Explaining the existence of such massive galaxies close to the dawn of time would require scientists to revisit either some basic rules of cosmology or the understanding of how the first galaxies were seeded from small clouds of stars and dust.
“It turns out we found something so unexpected it actually creates problems for science,” said Leja. “It calls the whole picture of early galaxy formation into question.”
Existing models suggest that after a period of rapid expansion, the universe spent a few hundred million years cooling down enough for gas to coalesce and collapse into the first stars and galaxies began to form, a period known as the dark ages.
“The discovery of such massive galaxies so soon after the big bang suggests that the dark ages may not have been so dark after all, and that the universe may have been awash with star formation far earlier than we thought,” said Dr Emma Chapman, an astrophysicist at the University of Nottingham, who was not involved in the latest observations.
Chapman said that further observations would be required to confirm the discovery before existing models could be abandoned. “Saying that, with the pace that JWST has been upturning theories and revolutionising whole fields, it wouldn’t surprise me if it were true!” she added.
The team are planning to obtain spectrum images, which can provide more accurate distance information and allow better estimates of mass. “A spectrum will immediately tell us whether or not these things are real,” Leja said.
Quelle: The Guardian
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Update: 25.02.2023
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James Webb Space Telescope reveals packed stars in Milky Way's oldest cluster (photos)
Creatures living on a planet inside the M92 star cluster would see a night sky illuminated by stars thousands of times brighter than those we see from Earth.
Image of the globular cluster Messier 92 (M92) captured by the James Webb Space Telescope's NIRCam instrument. The black strip in the center is a chip gap, the result of the separation between NIRCam's two long-wavelength detectors. The gap covers the dense center of the cluster, which is too bright to capture at the same time as the fainter, less dense outskirts of the cluster. (Image credit: NASA, ESA, CSA, Alyssa Pagan (STScI))
The James Webb Space Telescope has peered inside one of the oldest star clusters of our Milky Way galaxy, revealing a region of our galactic halo teeming with brilliant stars.
The James Webb Space Telescope observed the Messier 92 globular cluster, also known as M92, early after coming online last summer. It took only one hour to capture the sparkling image above, according to a statement(opens in new tab) by the Space Telescope Science Institute, which operates the observatory and released the image on Feb. 22.
Primarily built to study the most distant objects in the far-away reaches of the universe, Webb easily detected the multitude of stars inhabiting the M92 cluster some 27,000 light-years away, including the dim and cool ones that were invisible to its predecessor, the Hubble Space Telescope. Some of the stars in this image are tiny, only 0.1 the mass of our sun, Roger Cohen, an astronomer at Rutgers University and one of the scientists behind the observations, said in the statement.
"This is very close to the boundary where stars stop being stars," Cohen said. "Below this boundary are brown dwarfs, which are so low-mass that they're not able to ignite hydrogen in their cores."
The image, captured by Webb's Near Infrared Camera (NIRCam), reveals only a small portion of the M92 cluster. The entire cluster is about 100 light-years wide and is teeming with 300,000 stars. If an inhabited planet like Earth were to orbit one of those stars, the creatures on its surface would have a magnificent view of the night sky, which would shine with thousands of stars that would be thousands of times brighter than those humans can see from Earth.
M92 is one of the oldest globular clusters in the Milky Way, consisting of stars that formed 12 to 13 billion years ago, when the universe was only hundreds of millions years old.
Detail of the globular cluster Messier 92 (M92) captured by Webb's NIRCam instrument. This field of view covers the lower left quarter of the right half of the full image. The image shows stars at different distances from the center, which helps astronomers understand the motion of stars in the cluster, and the physics of that motion. (Image credit: NASA, ESA, CSA, Alyssa Pagan (STScI)
"It contains some of the oldest stars that we can find, or at least that we can resolve and characterize well," said astronomer Matteo Correnti of the Italian Space Agency, who helped analyze the data, in the statement.
By studying ancient clusters such as M92, astronomers can gain important insights into the history of not only our Milky Way galaxy, but the entire universe.
"Globular clusters like M92 are very important for our understanding of stellar evolution," astronomer Alessandro Savino of the University of California, another member of the Webb science team, said in the statement. "For decades they have been a primary benchmark for understanding how stars work, how stars evolve. M92 is a classic globular cluster. It's close by; we understand it relatively well; it's one of our references in studies of stellar evolution and stellar systems."
Most of the stars in the cluster have formed at about the same time and contain the same chemical elements. Some of these stars, however, are more massive than others, and Webb can help better describe the entire population.
Quelle: SC
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Update:7.03.2023
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James Webb Space Telescope 'sees triple' with help from Einstein (photos)
Using gravitational lensing and a massive galaxy cluster located 3.2 billion light-years away the powerful space telescope replicated a distant galaxy three times in a single image.
A stunning new image from the James Webb Space Telescope shows a supernova hosting galaxy not once, not twice, but three times at different points in time.
This seemingly time-defying image by the James Webb Space Telescope (JWST) was possible thanks to the massive gravitational influence of a foreground galactic cluster and a light-bending phenomenon predicted by Albert Einsteinover a century ago called "gravitational lensing."
In his theory of general relativity, Einstein predicted that mass warps the very fabric of space and time, or "spacetime." This is analogous to placing a ball on a stretched rubber sheet, with the ball causing a dent in the sheet. The greater the mass of the ball the larger the degree of warping it causes. This is also true in the case of spacetime, stars cause a greater "warp" than planets, and galaxies cause a greater warping of space than stars.
This warping affects the passage of light as it travels past the object of mass from a background object. In extreme cases, because light can take different paths around the lensing object from the background lensed object on its way to us, it can cause the background object to be magnified or even appear at multiple points in the sky. That means this phenomenon, "gravitational lensing" has become a powerful tool for astronomers in studying very distant objects.
A closer look at the three instances of the same red galaxy seen image from the James Webb Space Telescope at different times. (Image credit: ESA/Webb, NASA & CSA, P. Kelly)
The lensing object in this new JWST image is the galactic cluster RX J2129, located around 3.2 billion light-years away in the constellation Aquarius. RX J2129 is lensing a background red-colored supernova-hosting galaxy replicating it.
The supernova explosion was discovered by astronomers using the Hubble Space Telescope and is a Type Ia supernova designated AT 2022riv. These are often referred to as "standard candles" by astronomers because of how uniform their light is. This uniformity means that Type Ia supernovas can actually be used as a tool of measure cosmic distances because at the same distance, they would look exactly the same.
As a gravitational lens, RX J2129 has created three images of this galaxy that aren't the same in size, position, or even age because of the different paths the light from the background galaxy takes and thus the different times it arrives at the JWST.
The unannotated image from the James Webb Space Telescope showing a large elliptical galaxy surrounded by many smaller similar galaxies, including the galaxy cluster RX J2129 and upper right. (Image credit: ESA/Webb, NASA & CSA, P. Kelly)
The light that follows the longest path shows the background galaxy at its oldest age and at a time when its supernova was still occurring. The next image from the second longest path shows the galaxy just 320 days later, and the last one with the shortest light path 1,000 days after the first. In both of these later images, the supernova AT 2022riv has already faded from view.
Also appearing in the upper right-hand corner of the image are several background objects that due to the warping effect of gravitational lensingappear as concentric arcs of light.
The observations were made by the JWST using its Near-InfraRed Camera(opens in new tab)(NIRSpec) which was able to measure the brightness of AT 2022riv, a very distant and thus early supernova. The powerful space telescope has also been to perform spectroscopy on the light from the event, which should allow this distant supernova to be compared to more recently occurring Type Ia supernovas in the local universe.
This comparison could be used to test the accuracy of using these supernovae when measuring distances, thus verifying the results of one of astronomy's most useful tools.
Quelle:SC
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Update: 9.03.2023
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James Webb Space Telescope spots galaxy from early universe rich in star formation
'We found this galaxy to be super-chemically abundant, something none of us expected.'
A gravitationally lensed view of a ring-shaped slice of the galaxy SPT0418-47, as seen by the ALMA array in Chile. Recent observations by NASA's James Webb Space Telescope reveal that the galaxy has a satellite that's rich in star formation. (Image credit: ALMA (ESO/NAOJ/NRAO), Rizzo et al.)
New images from NASA's James Webb Space Telescope (JWST) have revealed that a well-known early galaxy has an overshadowed companion that is abundant with star formation.
JWST's initial target was SPT0418-47, one of the brightest dusty, star-forming galaxies in the early universe. Given it is an extremely distant galaxy — it lies about 12 billion light-years from Earth — its light is bent and magnified by the gravity of another galaxy in the foreground (located between SPT0418-47 and the space telescope), creating a near perfect circle called an Einstein ring.
Using the JWST, astronomers were able to get a clearer view of SPT0418-47 and spotted a curious blob of light shining near the galaxy's outer edge. As it turns out, the blob represents a companion galaxy previously overshadowed by the light of the foreground galaxy, according to a statement(opens in new tab) from Cornell University.
"We found this galaxy to be super-chemically abundant, something none of us expected," Bo Peng, lead author of the study and a doctoral student in astronomy at Cornell, said in the statement. "JWST changes the way we view this system and opens up new venues to study how stars and galaxies formed in the early universe."
Earlier observations of SPT0418-47 using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile contained hints of the companion, which, at the time, were interpreted as random noise, the researchers said.
Using the JWST, the researcher discovered that the companion galaxy, called SPT0418-SE, is within about 16,000 light-years of SPT0418-47. By comparison, the Magellanic Clouds — a pair of dwarf galaxy companions to the Milky Way — are located roughly 160,000 light-years away from us.
The close proximity of SPT0418-47 and SPT0418-SE suggests these galaxies are bound to interact or merge with one another eventually. In turn, this galactic pair could shed light on how early galaxies evolved into larger ones, given SPT0418-47 is believed to have formed when the universe was only 1.4 billion years old, according to the statement.
Interestingly, SPT0418-SE is believed to have already hosted multiple generations of stars, despite its young age. Both of the galaxies have a mature metallicity — or large amounts of elements like carbon, oxygen and nitrogen that are heavier than hydrogen and helium — which is similar to the sun. However, our sun is 4.5 billion years old and inherited most of its metals from previous generations of stars that were eight billion years old, the researchers said.
"We are seeing the leftovers of at least a couple of generations of stars having lived and died within the first billion years of the universe's existence, which is not what we typically see," study co-author Amit Vishwas, a research associate at the Cornell Center for Astrophysics and Planetary Sciences, said in the same statement.
"We speculate that the process of forming stars in these galaxies must have been very efficient and started very early in the universe, particularly to explain the measured abundance of nitrogen relative to oxygen, as this ratio is a reliable measure of how many generations of stars have lived and died," Vishwas said.
The new findings were published Feb. 17(opens in new tab) in the Astrophysical Journal Letters.
Quelle:SC
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Update: 12.03.2023
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First images released from James Webb Space Telescope’s largest general observer program
Mosaic images from the COSMOS-Web program offer a treasure trove of early galaxies
Images of four example galaxies selected from the first epoch of COSMOS-Web NIRCam observations, highlighting the range of structures that can be seen. In the upper left is a barred spiral galaxy; in the upper right is an example of a gravitational lens, where the mass of the central galaxy is causing the light from a distant galaxy to be stretched into arcs; on the lower left is nearby galaxy displaying shells of material, suggesting it merged with another galaxy in its past; on the lower right is a barred spiral galaxy with several clumps of active star formation. Image credit: COSMOS-Web/Kartaltepe, Casey, Franco, Larson, et al./RIT/UT Austin/IAP/CANDIDE
The first images from the largest program in the James Webb Space Telescope’s first year show many types of galaxies, including dazzling examples of spiral galaxies, gravitational lensing, and evidence of galaxy mergers. Scientists from the COSMOS-Web program released mosaic images taken in early January by JWST’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI).
COSMOS-Web aims to map the earliest structures of the universe and will create a wide and deep survey of up to 1 million galaxies. Over the course of 255 hours of observing time, COSMOS-Web will map 0.6 square degrees of the sky with NIRCam, roughly the size of three full moons, and 0.2 square degrees with MIRI.
The first epoch of COSMOS-Web MIRI observations obtained on Jan. 5-6, 2023. Covering six visits, the MIRI data are distributed in six non-overlapping tiles and include data from both the MIRI imager and Lyot Coronograph field of view. At left is a comparison between Spitzer IRAC channel 4 (8μm) data and MIRI 7.7μm data in a 40′′ × 40′′ zoom-in panel. Image credit: COSMOS-Web/Kartaltepe, Casey, Harish, Liu, et al./RIT/UT Austin/IAP/CANDIDE
“It’s incredibly exciting to get the first data from the telescope for COSMOS-Web,” said principal investigator Jeyhan Kartaltepe, an associate professor at Rochester Institute of Technology’s School of Physics and Astronomy. “Everything worked beautifully and the data are even better than we expected. We’ve been working really hard to produce science quality images to use for our analysis and this is just a drop in the bucket of what’s to come.”
Kartaltepe is co-leading COSMOS-Web with principal investigator Caitlin Casey, an associate professor at The University of Texas at Austin. The international team includes nearly 100 astronomers from all over the world.
“This first snapshot of COSMOS-Web contains about 25,000 galaxies—an astonishing number larger than even what sits in the Hubble Ultra Deep Field,” said Casey. “It’s one of the largest JWST images taken so far. And yet it’s just 4 percent of the data we will get for the full survey. When it is finished, this deep field will be astoundingly large and overwhelmingly beautiful.”
The first epoch of COSMOS-Web NIRCam observations obtained on Jan. 5-6, 2023, including the F115W, F150W, F277W, and F444W filters as a color composite. These data cover six visits or pointings out of a total of 152 visits. The total area covered by NIRCam here is ∼77arcmin^2. The relative position of this mosaic in the survey is shown at upper left. At lower left are several zoomed-in 10′′ × 10′′ cutouts and one 16′′ × 16′′ cutout showing specific galaxies selected from these first data. Image credit: COSMOS-Web/Kartaltepe, Casey, Franco, Larson, et al./RIT/UT Austin/IAP/CANDIDE
COSMOS-Web has three primary science goals: furthering our understanding of the Reionization Era, roughly 200,000 to 1 billion years after the Big Bang; identifying and characterizing early massive galaxies in the first 2 billion years; and studying how dark matter has evolved with the stellar content of galaxies. COSMOS-Web is the widest area JWST will observe in its first year, enabling the study of galaxies across a wide range of local environments. The images taken so far show incredible detail when compared with those taken previously by other observatories such as the Hubble Space Telescope and Spitzer Space Telescope.
The mosaics were created from six pointings of the telescope taken January 5-6. The telescope will take 77 pointings, roughly half the field, in April and May, and the remaining 69 pointings are scheduled to take place in December 2023 and January 2024.
“JWST has delivered such stunning images of this region that sources are literally popping out in every small patch of the observed sky,” said Santosh Harish, a postdoctoral research associate at RIT. “What were thought to be compact objects based on the best images we had so far, the JWST observations are now able to resolve these objects into multiple components, and in some cases even reveal the complex morphology of these extragalactic sources. With these first observations, we have just barely scratched the surface of what is to come with the completion of this program, next year.”
An overview of COSMOS-Web’s survey design, implementation, and outlook is available on ArXiv. For more information, including downloadable high-resolution images taken for the COSMOS-Web program, go to the COSMOS website.
Quelle: Rochester Institute of Technology
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Update: 15.03.2023
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NASA’s Webb Telescope Captures Rarely Seen Prelude to Supernova
The rare sight of a Wolf-Rayet star – among the most luminous, most massive, and most briefly detectable stars known – was one of the first observations made by NASA’s James Webb Space Telescope in June 2022. Webb shows the star, WR 124, in unprecedented detail with its powerful infrared instruments. The star is 15,000 light-years away in the constellation Sagittarius.
Massive stars race through their lifecycles, and only some of them go through a brief Wolf-Rayet phase before going supernova, making Webb’s detailed observations of this rare phase valuable to astronomers. Wolf-Rayet stars are in the process of casting off their outer layers, resulting in their characteristic halos of gas and dust. The star WR 124 is 30 times the mass of the Sun and has shed 10 Suns’ worth of material – so far. As the ejected gas moves away from the star and cools, cosmic dust forms and glows in the infrared light detectable by Webb.
The origin of cosmic dust that can survive a supernova blast and contribute to the universe’s overall “dust budget” is of great interest to astronomers for multiple reasons. Dust is integral to the workings of the universe: It shelters forming stars, gathers together to help form planets, and serves as a platform for molecules to form and clump together – including the building blocks of life on Earth. Despite the many essential roles that dust plays, there is still more dust in the universe than astronomers’ current dust-formation theories can explain. The universe is operating with a dust budget surplus.
Webb opens up new possibilities for studying details in cosmic dust, which is best observed in infrared wavelengths of light. Webb’s Near-Infrared Camera (NIRCam) balances the brightness of WR 124’s stellar core and the knotty details in the fainter surrounding gas. The telescope’s Mid-Infrared Instrument (MIRI) reveals the clumpy structure of the gas and dust nebula of the ejected material now surrounding the star. Before Webb, dust-loving astronomers simply did not have enough detailed information to explore questions of dust production in environments like WR 124, and whether the dust grains were large and bountiful enough to survive the supernova and become a significant contribution to the overall dust budget. Now those questions can be investigated with real data.
Stars like WR 124 also serve as an analog to help astronomers understand a crucial period in the early history of the universe. Similar dying stars first seeded the young universe with heavy elements forged in their cores – elements that are now common in the current era, including on Earth.
Webb’s detailed image of WR 124 preserves forever a brief, turbulent time of transformation, and promises future discoveries that will reveal the long-shrouded mysteries of cosmic dust.
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency), and CSA (Canadian Space Agency).
Quelle:NASA