A cosmic construction project

MACS J0553.4-3342

A galaxy cluster in deep space. It is filled with elliptical galaxies: small, bright white glowing ovals. The two largest elliptical galaxies, left and right of center, are bright cores that radiate light. Unrelated, distant galaxies are scattered around as red smudges and dots.Many of these are stretched out into red arcs and lines by the galaxy cluster’s strong gravity, creating multiple images in places. Numerous spiral galaxies and bright stars appear in the foreground. Credit: ESA/Webb, NASA & CSA, S. Fujimoto

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In today’s Picture of the Month from the NASA/ESA/CSA James Webb Space Telescope we are taken on a visit to a building site of significant scale. The project is a galaxy cluster named MACS J0553.4-3342, located in the constellation Columba (the Dove).

MACS J0553.4-3342 is situated at a redshift of 0.412. Redshift is a measure of how much the cluster’s light has been stretched by the expansion of the Universe over the course of its long journey to Webb’s mirrors; this unassuming number tells us that we are seeing MACS J0553.4-3342 as it was 4.4 billion years in the past. But for a galaxy cluster, this is relatively young. In fact, observations with the NASA/ESA Hubble Space Telescope and other telescopes show a cluster still in the process of being built.

MACS J0553.4-3342 is composed of two sub-clusters — roughly equal in mass — that are actively merging. The two subclusters have already slammed through each other and travelled over one million light-years apart, but they will eventually come back together again and again until they finally merge. The construction process is messy, and MACS J0553.4-3342 is filled with extremely hot gas that radiates powerful X-rays. Each subcluster is anchored on an immensely bright and massive elliptical galaxy, which are easily identifiable as the two brightest points in the centre of this scene with the largest glowing halos around them. The many smaller white elliptical galaxies are bound to one of the two subclusters by gravity, and will be incorporated into the final galaxy cluster. This image also features many foreground galaxies — spirals and dusty discs that are unrelated to MACS J0553.4-3342 — and prominent bright stars in our own Milky Way galaxy.

Even mid-way through its construction, the titanic clumps of matter swirling around in this galaxy cluster have built a device that is already very useful for us here on Earth: a gravitational lens. The extreme and concentrated mass in MACS J0553.4-3342 curves light with its gravity, similar to how a glass lens bends and focuses light. In this image you can see prominent orange, stretched-out arcs alongside each of the subclusters. These arcs are images of distant background galaxies, whose light has been warped by the galaxy cluster’s gravitational pull. The arc on the left side, three bright spots joined together, is actually three images of a single background galaxy! A forest of smaller arcs and lines are scattered across the image too; such a fantastic view appears in few other places in the Universe.

Look in the right spot, however, and this galaxy cluster turns from a distorting funhouse mirror into a precision scientific device. The gravitational lensing focuses light, magnifying objects and enhancing their brightness so if they lie in exactly the right place, background galaxies and even individual stars that would have been far too faint and distant to spot will be made visible. By carefully mapping out the mass of the cluster, researchers can reconstruct where and how strongly it distorts light from our point of view, then search for serendipitously-magnified distant objects to study. The arcs we can see in MACS J0553.4-3342 already show a few galaxies from less than a billion years after the Big Bang.

This image, taken with Webb’s Near-Infrared Camera (NIRCam), stems from a survey programme named VENUS (#6882). Astronomers aimed to create a collection of deep, high-quality images of massive galaxy clusters like MACS J0553.4-3342 across a wide range of infrared wavelengths, greatly expanding the area covered by Webb’s sensitive instruments. Researchers can then scour the clusters for distant and faint objects that have been brightened through gravitational lensing, from young galaxies and low-mass black holes to supernova explosions and individual stars. Gravitational lensing has been key to many of Webb’s most dramatic discoveries in recent years, and having many more examples of it allows us to systematically study the distant past and the evolutionary stages of the galaxies, stars and black holes we see today.

Source: ESA/Webb/potm

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Links

• Pan video: MACS J0553.4-3342
• Zoom video: MACS J0553.4-3342

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Webb unveils young stars across every stage of formation

Star-forming molecular cloud - Constellation Orion 

An area inside a star-forming molecular cloud. The background is covered with layers of gas and dust in blue, green and yellowish colours. Thicker clumps of cold dust, dark brown to black, block out light completely. Stars lie among and atop the clouds, from small orange ones to large white or blue ones. Waves and streams of glowing whitish gas are created by jets from protostars colliding with the surrounding material. Credit: ESA/Webb, NASA & CSA, T. Megeath, M. Zamani (ESA/Webb) - Acknowledgement: M. H. Özsaraç

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For this NASA/ESA/CSA James Webb Space Telescope Picture of the Month we return to the constellation Orion (the Hunter), a location familiar to Webb. This area of the sky is replete with star-forming clouds that make up a complex hundreds of light-years across. We find ourselves in the giant molecular cloud Orion A, of which the familiar Orion Nebula (also known as M42) is just a part; Webb has taken both close-up and wide-angle looks at M42 before.

The target of these observations, however, requires us to look behind the Orion Nebula. Behind the stars, gas and dust of M42 is a long, massive filament of cold gas and dust called (somewhat confusingly) the Orion Molecular Clouds, which is divided into four parts, OMC-1 through OMC-4. OMC-1 sits immediately behind M42, to the north are OMC-2 and OMC-3, and OMC-4 lies to the south.

This image shows just a small, northern portion of OMC-2, located 1280 light-years from Earth and a little north of the Orion Nebula. Every stage of star formation — from the youngest stellar embryos, to protoplanetary discs, to newly-minted pre-main sequence stars — is contained within just this scene, which stretches 150 light-years across. The intense star-forming activity has produced an impressive display of billowing outflows and sparkling stars atop swirling layers of gas and dark, obscuring clouds.

Molecular clouds such as OMC-2 are vast clumps of gas much more dense than the rest of interstellar space. This density allows complex molecules to form, protected from the radiation given off by other stars, and it means that gravity can cause the cloud to collapse and form stars. The earliest stage of this process is a protostar - a growing star that is being fed gas from the surrounding cloud through a spinning disc of gas. As gas falls onto the protostar, it heats up, powering the glow of the protostar. The immense amount of energy acquired during this process is unleashed in fierce jets of gas from the poles of the star, frequently seen as twin glowing outflows that mark the location of a protostar.

The abundance of protostars forming here in OMC-2 has created many spectacular outflows, large and small. Jets emitted from the young stars form high-speed shockwaves that sweep through the dense material around them; where the shockwaves are impacting the gas, it heats up and glows brightly, creating sharp ridges. Zoom in to observe the fine details in these shockwaves, as well as spot the smaller outflows from younger protostars. See if you can spot the location of hidden protostars, still so deeply obscured by their dusty cradles that they can’t be seen directly, by following outflows! Compare these very young protostars to the most evolved examples: the large, bright stars which have cleared away the clouds that surrounded them and now illuminate OMC-2.

Webb’s Near-Infrared Camera (NIRCam) was used to capture this view of OMC-2. The thick gas and dust in and around the Orion Nebula blocks any light coming from OMC-2 at visible wavelengths, and the clouds in OMC-2 itself obscure the protostars that astronomers really want to find. Only in the infrared do we see these protostars begin to shine out from their cocoons of dust. In many places, the cold dust is so dense that it absorbs all or almost all light, creating dark globules. Orange, brown and some of the red colours mark warmer dust that absorbs some light and emits some of its own. The yellow to green gradient is largely emission from polycyclic aromatic hydrocarbons (PAHs), while light from stars and protostars scattered by dust grains is seen here primarily as blue and cyan hazes. Gas heated by the outflows creates the detailed, glowing red ridges.

The data was collected in observing programme #5804, which aims to study the star formation in OMC-2 and its immediate neighbour, OMC-3. Since these molecular clouds are so near to Earth, they are excellent laboratories to learn about the earliest stages of stellar evolution. Astronomers will use the data from Webb to investigate how the many outflows affect star formation in the two regions, how the ultraviolet emission from the young stars impacts chemistry in the circumstellar discs which one day will form planets, and how gas and dust accretes onto the tens of protostars in the region.

Source: ESA/Webb/potm

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Links

• Pan video: OMC-2
• Zoom video: OMC-2
• Space Sparks episode: OMC-2
• Image on ESA website

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A beacon of light in swirls of dust

A spiral galaxy shown in mid-infrared light. The image is dominated by an extremely bright glow from the galaxy’s nucleus. Six large and two smaller rays of light emit from the centre, which are diffraction spikes created by the telescope’s optics. The galaxy’s spiral arms are visible by two lines of glowing orange bubbles which whirl out into the disc. Swirling blue clouds of dust make up the rest of the galaxy. Credit:ESA/Webb, NASA & CSA, A. Leroy

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This latest Picture of the Month from the NASA/ESA/CSA James Webb Space Telescope features Messier 77 (M77), a barred spiral galaxy famous and appreciated among astronomers for its combination of relative proximity and spectacular features to study. It is located 45 million light-years away in the constellation Cetus (The Whale). This new image from Webb’s Mid-Infrared Instrument (MIRI) highlights its swirling spiral arms, the dust in its disc and its piercingly bright core like never before.

At the heart of M77 is a compact region filled with hot gas that handily outshines the rest of the galaxy put together, even overcoming the light-gathering capacity of Webb’s cameras. This is an active galactic nucleus (AGN), and it’s powered by M77’s central supermassive black hole, which is eight million times as massive as our Sun. Gas in the galaxy’s central regions is pulled by the strong gravity into a tight and rapid orbit around the black hole, where it crashes together and heats up, releasing tremendous amounts of radiation.

The bright orange lines appearing to radiate out from the centre of M77 are not actually a feature of the galaxy: they are a type of distortion that arises from the optical design of the telescope. Called diffraction spikes, they are created because the intense light from the unresolved AGN is bent (“diffracted”) very slightly at the edges of Webb’s hexagonal mirror panels and around one of the struts that hold up its secondary mirror. This distinctive six-plus-two-pointed pattern is the same for any image taken by Webb. For diffraction spikes to appear, the light source has to be very bright and very concentrated, so they’re most often seen on stars. But in some galaxies, as here, the nucleus is bright and compact enough to make diffraction spikes appear as well.

M77 is not just known for its easily visible AGN, but also as a prolific star-forming galaxy. The near-infrared image of M77 reveals a bar spanning across the central region, which doesn’t appear in visible-light images of the galaxy. The bar is enclosed by a bright ring, called a starburst ring, formed by the inner ends of M77’s two spiral arms. Starburst regions in galaxies are typified by extremely high star-formation rates. This ring is more than 6 000 light-years across and displays intense and widespread starbursts, visible in this image by the densely concentrated orange bubbles all around the ring. Since M77 is relatively close to Earth, this starburst ring is a very well-studied example of the phenomenon.

As an active spiral galaxy, M77’s disc is filled with gas and dust which is both a product of and fuel for future star formation. Webb’s MIRI fills out our view of the galaxy with the glow of interstellar dust grains emitted at longer wavelengths, shown here in blue. The dust forms a huge vortex of smoky, swirling filaments with cavities in between. The glowing orange bubbles carved out by newly formed star clusters are also prominently visible out along the galaxy’s arms.

Beyond Webb’s quite focused view, M77’s arms join into a faint extended ring of hydrogen gas thousands of light-years wide, where yet more star formation is taking place. Vast, tenuous filaments of hydrogen gas stretch across this ring and out into intergalactic space, forming an outermost layer around the galaxy. For the tentacle-like appearance of these filaments, M77 is also named the Squid Galaxy.

The data used to create this image are from an observing programme (#3707) that surveyed massive, nearby, star-forming galaxies to create a rich dataset useful for many scientific investigations. As can be seen here, the stunning resolution of Webb’s instruments reveals star clusters and rich reservoirs of gas, which can be used to explore the cycle of star formation, life and death in these and other galaxies.

Source: ESA/Webb/potm

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Links

• Messier 77 (MIRI + NIRCam image)
• Messier 77 (NIRCam image)
• Image on ESA website
• Space Sparks episode
• Pan video
• Transition video

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Dwarf stars in a glittering sky

Westerlund 2

A cluster of stars inside a large nebula. The clouds of gas and dust are predominantly bright red in colour and wispy, akin to flames. They are clumped in the bottom-left corner. Other clouds, deeper in the cluster behind many of the stars, appear pale pink. The stars are concentrated in the top half of the image and are mostly small, bright white and six-pointed. They cast blue light over the nebula. Other stars with very long spikes surrounding them lie in the foreground. Credit: ESA/Webb, NASA & CSA, V. Almendros-Abad, M. Guarcello, K. Monsch, and the EWOCS team.

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The final ESA/Webb Picture of the Month feature for 2025 showcases a festive-looking region filled with glowing clouds of gas and thousands of sparkling stars. This star cluster, known as Westerlund 2, resides in a stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina (the Keel).

This image of Westerlund 2 uses data from Webb’s Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI). The cluster measures between 6 light-years and 13 light-years across, and is host to some of our Milky Way galaxy's hottest, brightest, and most massive stars. It was also the feature of Hubble’s 25th anniversary image in 2015.

;: This new Webb image captures the bright, brilliant cluster near the top that is packed with young, massive stars whose intense light shapes the entire scene. Below and around them, swirls of orange and red gas form sculpted walls and tangled clouds - material that is being pushed, eroded, and illuminated by the cluster’s powerful radiation. Threaded throughout the view are countless tiny stars just beginning to shine, some still surrounded by the gas and dust from which they formed. The soft blues and pinks are wisps of thinner material drifting between the denser clouds. Scattered across the field are also many bright stars much closer to us, whose sharp, star-shaped patterns are created by Webb’s optics. The result is a vivid portrait of a stellar nursery in action, where intense energy from newborn stars carves dramatic shapes into the surrounding nebula and drives the ongoing cycle of star formation.

These new Webb observations of Westerlund 2 have revealed, for the first time, the full population of brown dwarfs in this extremely massive young star cluster, including objects as small as about 10 times the mass of Jupiter. This data is allowing astronomers to find several hundred stars with discs in various evolutionary states to facilitate our understanding of how discs evolve and how planets form in such massive young clusters. This image was developed using data from Webb’s programme #3523 (M. Guarcello) as part of the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS).

Source: ESA/Webb/potm

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Links

• Slider tool: Webb and Hubble’s views of Westerlund 2
• Pan video: Westerlund 2 (NIRCam and MIRI image)
• Transition video: Webb and Hubble’s views of Westerlund 2
• Image on ESA website

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Webb witnesses a feasting supermassive black hole in the early Universe

PR Image weic2522a
CANUCS-LRD-z8.6 in MACS J1149.5+2223

PR Image weic2522b
MACS J1149.5+2223

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Videos

 

PR Video weic2522a
Pan video: Galaxy cluster MACS J1149.5+2223

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Researchers using the NASA/ESA/CSA James Webb Space Telescope have confirmed an actively growing supermassive black hole within a galaxy just 570 million years after the Big Bang. Part of a class of small, very distant galaxies that have mystified astronomers, CANUCS-LRD-z8.6 represents a vital piece of this puzzle that challenges existing theories about the formation of galaxies and black holes in the early Universe. The discovery connects early black holes with the luminous quasars we observe today.

Over its first three years, Webb's surveys of the early Universe have turned up an increasing number of small, extremely distant, and strikingly red objects. These so-called Little Red Dots (LRDs) remain a tantalising mystery to astronomers, despite their unexpected abundance. The discovery in CANUCS-LRD-z8.6, made possible by Webb’s exceptional capabilities, has assisted in this hunt for answers. Webb’s Near-Infrared Spectrograph (NIRSpec) enabled researchers to observe the faint light from this distant galaxy and detect key spectral features that point to the presence of an accreting black hole.

Roberta Tripodi, lead author of the study and a researcher of the University of Ljubljana FMF, in Slovenia and INAF - Osservatorio Astronomico di Roma, in Italy, explained: "This discovery is truly remarkable. We’ve observed a galaxy from less than 600 million years after the Big Bang, and not only is it hosting a supermassive black hole, but the black hole is growing rapidly - far faster than we would expect in such a galaxy at this early time. This challenges our understanding of black hole and galaxy formation in the early Universe and opens up new avenues of research into how these objects came to be."

The team analysed the galaxy's spectrum, which showed gas which had been highly ionised by energetic radiation, and suggested it was rotating quickly around a central source. These features are key characteristics of an accreting supermassive black hole. The precise spectral data yielded an estimate of the black hole’s mass, revealing it to be unusually large for such an early stage in the Universe, and showed that CANUCS-LRD-z8.6 is compact and has not yet produced many heavy elements — a galaxy at an early stage of its evolution. This combination makes it an intriguing subject for study.

Additionally, the Webb spectroscopy allowed the team to measure how much energy is emitted at different wavelengths, from which they were able to characterise the galaxy’s physical properties. This allowed them to determine the mass of the galaxy’s stars and compare it with the black hole’s mass. "The data we received from Webb was absolutely crucial,” added Dr. Nicholas Martis, a collaborator from the University of Ljubljana, FMF, who helped analyse the spectrum of the source. “The spectral features revealed by Webb provided clear signs of an accreting black hole at the centre of the galaxy, something that could not have been observed with previous technology. What makes this even more compelling is that the galaxy’s black hole is overmassive compared to its stellar mass. This suggests that black holes in the early Universe may have grown much faster than the galaxies that host them."

Astronomers have previously observed that the mass of a supermassive black hole and its host galaxy are linked: the larger a galaxy grows, the larger its central black hole also becomes. CANUCS-LRD-z8.6 is the most massive host galaxy known at such an early time, yet its central black hole is even more massive than we would expect, defying the usual relation. The result suggests that black holes may have formed and started growing at an accelerated pace in the early Universe, even in relatively small galaxies.

"This discovery is an exciting step in understanding the formation of the first supermassive black holes in the Universe,” explained Prof. Maruša Bradač, leader of the group at the University of Ljubljana, FMF. “The unexpected rapid growth of the black hole in this galaxy raises questions about the processes that allowed such massive objects to emerge so early. As we continue to analyse the data, we hope to find more galaxies like CANUCS-LRD-z8.6, which could provide us with even greater insights into the origins of black holes and galaxies."

The team is already planning additional observations with the Atacama Large Millimetre/submillimetre Array (ALMA) and Webb to further study the cold gas and dust in the galaxy and to refine their understanding of the black hole’s properties. The ongoing research into this LRD is poised to answer crucial questions about the early Universe, including how black holes and galaxies co-evolved in the first billion years of cosmic history.

As astronomers continue to explore the early Universe with JWST, further surprises are expected to emerge, offering an increasingly detailed picture of how the first supermassive black holes grew and evolved, setting the stage for the formation of the luminous quasars that light up the Universe today.

The results were obtained by the CANUCS collaboration from the Webb observing programme #1208 (PI: C. J. Willott) and have been published today in Nature Communications.

Source: ESA/Webb/News/Press Releases

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More information

Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Image Credit: ESA/Webb, NASA & CSA, G. Rihtaršič (University of Ljubljana, FMF), R. Tripodi (University of Ljubljana, FMF)

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Links

• Science paper
• Release on ESA website

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Contacts:

Roberta Tripodi
University of Ljubljana FMF, Slovenia
Email: roberta.tripodi@inaf.it

Bethany Downer
ESA/Webb Chief Science Communications Officer
Email: Bethany.Downer@esawebb.org

ESA Newsroom and Media Relations Office
Email: media@esa.int

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The Red Spider Nebula, caught by Webb

NGC 6537/Red Spider Nebula
Credit: ESA/Webb, NASA & CSA, J. H. Kastner (Rochester Institute of Technology)

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This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month features a cosmic creepy-crawly called NGC 6537 — the Red Spider Nebula. Using its Near-InfraRed Camera (NIRCam), Webb has revealed never-before-seen details in this picturesque planetary nebula with a rich backdrop of thousands of stars.

Planetary nebulae like the Red Spider Nebula form when ordinary stars like the Sun reach the end of their lives. After ballooning into cool red giants, these stars shed their outer layers and cast them into space, exposing their white-hot cores. Ultraviolet light from the central star ionises the cast-off material, causing it to glow. The planetary nebula phase of a star’s life is as fleeting as it is beautiful, lasting only a few tens of thousands of years.

The central star of the Red Spider Nebula is visible in this image, glowing just brighter than the webs of dusty gas that surround it. The surprising nature of the nebula’s tremendously hot and luminous central star has been revealed by Webb’s NIRCam. In optical-wavelength images, such as from the NASA/ESA Hubble Space Telescope, the star appears faint and blue. But in the NIRCam images, it shows up as red: thanks to its sensitive near-infrared capabilities, Webb has revealed a shroud of hot dust surrounding the central star. This hot dust likely orbits the central star, in a disc structure.

Though only a single star is visible in the Red Spider’s heart, a hidden companion star may lurk there as well. A stellar companion could explain the nebula’s shape, including its characteristic narrow waist and wide outflows. This hourglass shape is seen in other planetary nebulae such as the Butterfly Nebula, which Webb also recently observed.

Webb’s new view of the Red Spider Nebula reveals for the first time the full extent of the nebula’s outstretched lobes, which form the ‘legs’ of the spider. These lobes, shown in blue, are traced by light emitted from H2 molecules, which contain two hydrogen atoms bonded together. Stretching over the entirety of NIRCam’s field of view, these lobes are shown to be closed, bubble-like structures that each extend about 3 light-years. Outflowing gas from the centre of the nebula has inflated these massive bubbles over thousands of years.

Gas is also actively jetting out from the nebula’s centre, as these new Webb observations show. An elongated purple ‘S’ shape centred on the heart of the nebula follows the light from ionised iron atoms. This feature marks where a fast-moving jet has emerged from near the nebula’s central star and collided with material that was previously cast away by the star, sculpting the rippling structure of the nebula seen today.

The observations used to create this image come from Webb GO programme #4571 (PI: J. Kastner) as part of a joint Chandra-JWST observing programme, which aims to understand how bipolar planetary nebulae like the Red Spider Nebula are shaped by the outflows and jets that emerge from the stars at their cores.

Source: ESA/Webb/potm

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Links

• Science paper
• Annotated image
• Slider tool: Hubble and Webb's views of NGC 6537
• Image on ESA website
• Pan video
• Transition Video: Hubble and Webb's views of NGC 6537
• Space Sparks Episode

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Dusty wisps round a dusty disc

A wide-field image of IRAS 16594-4656 taken by the James Webb Space Telescope. The nebula’s bright core is split by a narrow dark band, with expansive rainbow lobes of light and colour radiating outward. Numerous background galaxies and stars are visible across the field. redit: ESA/Webb, NASA & CSA, M. Villenave et al. Hi-rs image

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For this new Picture of the Month feature, the NASA/ESA/CSA James Webb Space Telescope has provided a fantastic new view of IRAS 04302+2247, a planet-forming disc located about 525 light-years away in a dark cloud within the Taurus star-forming region. With Webb, researchers can study the properties and growth of dust grains within protoplanetary discs like this one, shedding light on the earliest stages of planet formation.

In stellar nurseries across the galaxy, baby stars are forming in giant clouds of cold gas. As young stars grow, the gas surrounding them collects in narrow, dusty protoplanetary discs. This sets the scene for the formation of planets, and observations of distant protoplanetary discs can help researchers understand what took place roughly 4.5 billion years ago in our own Solar System, when the Sun, Earth, and the other planets formed.

IRAS 04302+2247, or IRAS 04302 for short, is a beautiful example of a protostar - a young star that is still gathering mass from its environment - surrounded by a protoplanetary disc in which baby planets might be forming. Webb is able to measure the disc at 65 billion kilometres across - several times the diameter of our Solar System. From Webb’s vantage point, IRAS 04302’s disc is oriented edge-on, so we see it as a narrow, dark line of dusty gas that blocks the light from the budding protostar at its centre. This dusty gas is fuel for planet formation, providing an environment within which young planets can bulk up and pack on mass.

When seen face-on, protoplanetary discs can have a variety of structures like rings, gaps and spirals. These structures can be signs of baby planets that are burrowing through the dusty disc, or they can point to phenomena unrelated to planets, like gravitational instabilities or regions where dust grains are trapped. The edge-on view of IRAS 04302’s disc shows instead the vertical structure, including how thick the dusty disk is. Dust grains migrate to the midplane of the disc, settle there and form a thin, dense layer that is conducive to planet formation; the thickness of the disc is a measure of how efficient this process has been.

The dense streak of dusty gas that runs vertically across this image cocoons IRAS 04302, blotting out its bright light such that Webb can more easily image the delicate structures around it. As a result, we’re treated to the sight of two gauzy nebulae on either side of the disc. These are reflection nebulae, illuminated by light from the central protostar reflecting off of the nebular material. Given the appearance of the two reflection nebulae, IRAS 04302 has been nicknamed the “Butterfly Star”.

This view of IRAS 04302 features observations from Webb's Near-InfraRed Camera (NIRCam) and its Mid-InfraRed Instrument (MIRI), combined with optical data from the NASA/ESA Hubble Space Telescope. Together, these powerful facilities paint a fascinating multiwavelength portrait of a planetary birthplace. Webb reveals the distribution of tiny dust grains as well as the reflection of near-infrared light off of dusty material that extends a large distance from the disc, while Hubble focuses on the dust lane as well as clumps and streaks surrounding the dust that suggest the star is still collecting mass from its surroundings as well as shooting out jets and outflows.

The Webb observations of IRAS 04302 were taken as part of the Webb GO programme #2562 (PI F. Ménard, K. Stapelfeldt). This programme investigates four protoplanetary discs that are oriented edge-on from our point of view, aiming to understand how dust evolves within these discs. The growth of dust grains in protoplanetary discs is believed to be an important step toward planet formation.

Source: ESA/Webb/potm

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Links:

• Close-up view of IRAS 04302+2247
• Science paper (M. Villenave et al.)
• Pan video
• Image on ESA website

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A fresh look at a classic deep field

An area of deep space with thousands of galaxies in various shapes and sizes on a black background. Most are circles or ovals, with a few spirals. More distant galaxies are smaller, down to being mere dots, while closer galaxies are larger and some appear to be glowing. Red and orange galaxies contain more dust or more stellar activity. Credit: ESA/Webb, NASA & CSA, G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the JADES Collaboration, the MIDIS collaboration, M. Zamani (ESA/Webb)

This image from the NASA/ESA/CSA James Webb Space Telescope revisits one of the most iconic regions of the sky, the Hubble Ultra Deep Field, through the eyes of two of Webb’s instruments. The result is a detailed view that reveals thousands of distant galaxies, some dating back to the earliest periods of cosmic history.

The field shown here, known as the MIRI Deep Imaging Survey (MIDIS) region, was observed with the three shortest-wavelength filters of Webb’s Mid-Infrared Instrument (MIRI) for nearly 100 hours in total. This included Webb's longest observation of an extragalactic field in one filter so far, producing one of the deepest views ever obtained of the Universe. Combined with data from Webb’s Near-Infrared Camera (NIRCam), this image allows astronomers to explore how galaxies formed and evolved over billions of years.

These deep observations have revealed more than 2500 sources in this tiny patch of sky. Among them are hundreds of extremely red galaxies — some of which are likely massive, dust-obscured systems or evolved galaxies with mature stars that formed early in the Universe’s history. Thanks to Webb’s sharp resolution, even at mid-infrared wavelengths, researchers can resolve the structures of many of these galaxies and study how their light is distributed, shedding light on their growth and evolution.

In this image, the colours that have been assigned to different kinds of infrared light highlight the fine distinctions astronomers can make with this deep data. Orange and red represent the longest mid-infrared wavelengths. The galaxies in these colours have extra features — such as high concentrations of dust, copious star formation, or an active galactic nucleus (AGN) at their centre — which emit more of this farther infrared light. Small, greenish-white galaxies are particularly distant, with high redshift. This shifts their light spectrum into the peak mid-infrared wavelengths of the data, which are depicted in white and green. Most of the galaxies in this image lack any such mid-infrared boosting features, leaving them most bright at shorter near-infrared wavelengths, which are depicted with blue and cyan colours.

By returning to this legacy field first made famous by the NASA/ESA Hubble Space Telescope, Webb is continuing and expanding the deep field tradition — revealing new details, uncovering previously hidden galaxies, and offering fresh insights into the formation of the first cosmic structures.

The MIRI observations were taken as part of the Webb programmes #1283 and #6511 (PI: G. Östlin).

Source: ESA/Webb/potm

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Link

• Science paper (G. Östlin et al.)
• Slider Tool
• Pan Video
• Transition video (with Hubble Ultra Deep Field)

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A glimpse of the distant past

Abell S1063

A field of galaxies in space, dominated by an enormous, bright-white elliptical galaxy that is the core of a massive galaxy cluster. Many other elliptical galaxies can be seen around it. Also around it are short, curved, glowing red lines, which are images of distant background galaxies magnified and warped by gravitational lensing. A couple of foreground stars appear large and bright with long spikes around them. Credit: ESA/Webb, NASA & CSA, H. Atek, M. Zamani (ESA/Webb). Acknowledgement: R. Endsley

The eye is first drawn, in this new NASA/ESA/CSA James Webb Space Telescope Picture of the Month, to the central mega-monster that is galaxy cluster Abell S1063. This behemoth collection of galaxies, lying 4.5 billion light-years from Earth in the constellation Grus (the Crane), dominates the scene. Looking more closely, this dense collection of heavy galaxies is surrounded by glowing streaks of light, and these warped arcs are the true object of scientists’ interest: faint galaxies from the Universe’s distant past.

Abell S1063 was previously observed by the NASA/ESA Hubble Space Telescope’s Frontier Fields programme. It is a strong gravitational lens: the galaxy cluster is so massive that the light of distant galaxies aligned behind it is bent around it, creating the warped arcs that we see here. Like a glass lens, it focuses the light from these faraway galaxies. The resulting images, albeit distorted, are both bright and magnified — enough to be observed and studied. This was the aim of Hubble’s observations, using the galaxy cluster as a magnifying glass to investigate the early Universe.

The new imagery from Webb’s Near-Infrared Camera (NIRCam) takes this quest even further back in time. This image showcases an incredible forest of lensing arcs around Abell S1063, which reveal distorted background galaxies at a range of cosmic distances, along with a multitude of faint galaxies and previously unseen features.

This image is what’s known as a deep field — a long exposure of a single area of the sky, collecting as much light as possible to draw out the most faint and distant galaxies that don’t appear in ordinary images. With 9 separate snapshots of different near-infrared wavelengths of light, totalling around 120 hours of observing time and aided by the magnifying effect of gravitational lensing, this is Webb’s deepest gaze on a single target to date. Focusing such observing power on a massive gravitational lens, like Abell S1063, therefore has the potential to reveal some of the very first galaxies formed in the early Universe.

The observing programme that produced this data, GLIMPSE (#3293, PIs: H. Atek & J. Chisholm), aims to probe the period known as Cosmic Dawn, when the Universe was only a few million years old. Studying the galaxies revealed by gravitational lensing has the potential to develop our understanding of the emergence of the first galaxies. Analysis of this NIRCam data by the GLIMPSE team has already produced candidates for galaxies that existed as early as 200 million years after the Big Bang, and hints of the elusive first population of stars in the Universe.

Links

• Image on ESA website
• Pan video
• Science paper: V. Kokorev et al.
• Science paper: S. Fujimoto et al.

Source: ESA/Webb/potm

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Spying a spiral through a cosmic lens

In the centre is an elliptical galaxy, seen as an oval-shaped glow around a small bright core. Around this is wrapped a broad band of light, appearing like a spiral galaxy stretched and warped into a ring, with bright blue lines drawn through it where the spiral arms have been stretched into circles. A few distant objects are visible around the ring on a black background. Credit: ESA/Webb, NASA & CSA, G. Mahler. Acknowledgement: M. A. McDonald

This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month features a rare cosmic phenomenon called an Einstein ring. What at first appears to be a single, strangely shaped galaxy is actually two galaxies that are separated by a large distance. The closer foreground galaxy sits at the center of the image, while the more distant background galaxy appears to be wrapped around the closer galaxy, forming a ring.

Einstein rings occur when light from a very distant object is bent (or ‘lensed’) about a massive intermediate (or ‘lensing’) object. This is possible because spacetime, the fabric of the Universe itself, is bent by mass, and therefore light travelling through space and time is bent as well. This effect is much too subtle to be observed on a local level, but it sometimes becomes clearly observable when dealing with curvatures of light on enormous, astronomical scales, such as when the light from one galaxy is bent around another galaxy or galaxy cluster.

When the lensed object and the lensing object line up just so, the result is the distinctive Einstein ring shape, which appears as a full circle (as seen here) or a partial circle of light around the lensing object, depending on the precision of the alignment. Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see.

The lensing galaxy at the center of this Einstein ring is an elliptical galaxy, as can be seen from the galaxy’s bright core and smooth, featureless body. This galaxy belongs to a galaxy cluster named SMACSJ0028.2-7537. The lensed galaxy wrapped around the elliptical galaxy is a spiral galaxy. Even though its image has been warped as its light travelled around the galaxy in its path, individual star clusters and gas structures are clearly visible.

The Webb data used in this image were taken as part of the Strong Lensing and Cluster Evolution (SLICE) survey (programme 5594), which is led by Guillaume Mahler at University of Liège in Belgium, and consists of a team of international astronomers. This survey aims to trace 8 billion years of galaxy cluster evolution by targeting 182 galaxy clusters with Webb’s Near-InfraRed Camera instrument. This image also incorporates data from two of the NASA/ESA Hubble Space Telescope’s instruments, the Wide Field Camera 3 and the Advanced Camera for Surveys.

Links

• Pan Video: Einstein ring in galaxy cluster SMACSJ0028.2-7537
• Image on ESA website

Source: ESA/Webb/potm

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Webb investigates a dusty and dynamic disc

HH 30 (in dark cloud LDN 1551)

A close-in image of a protoplanetary disc around a newly formed star. Many different wavelengths of light are combined and represented by separate and various colours. A dark line across the centre is the disc, corresponding to the densest parts of the disc, made of opaque dust: the star is hidden in here and creates a strong glow in the centre. A band going straight up is a jet, while other outflows above and below the disc, and a tail coming off to one side. Credit: ESA/Webb, NASA & CSA, Tazaki et al.

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This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month presents HH 30 in unprecedented resolution. This target is an edge-on protoplanetary disc that is surrounded by jets and a disc wind, and is located in the dark cloud LDN 1551 in the Taurus Molecular Cloud.

Herbig-Haro objects are small nebulae found in star formation regions, marking the locations where gas outflowing from young stars is heated into luminescence by shockwaves. HH 30 is an example of where this outflowing gas takes the form of a narrow jet. The source star is located on one end of the jet, hidden behind an edge-on protoplanetary disc that the star is illuminating.

HH 30 is of particular interest to astronomers. In fact, the HH 30 disc is considered the prototype of an edge-on disc, thanks to its early discovery with the NASA/ESA Hubble Space Telescope. Discs seen from this view are a unique laboratory to study the settling and drift of dust grains.

An international team of astronomers have used Webb to investigate the target in unprecedented detail. By combining Webb’s observations with those from the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA), the team was able to study the multiwavelength disc appearance of the system.

The long-wavelength data from ALMA trace the location of millimetre-sized dust grains, which are found in a narrow region in the central plane of the disc. The shorter-wavelength infrared data from Webb reveal the distribution of smaller dust grains. These grains are only one millionth of a metre across — about the size of a single bacterium. While the large dust grains are concentrated in the densest parts of the disc, the small grains are much more widespread.

These Webb observations were taken as part of the Webb GO programme #2562 (PI F. Ménard, K. Stapelfeldt), which aims to understand how dust evolves in edge-on discs like HH 30. Combined with the keen radio-wavelength eyes of ALMA, these observations show that large dust grains must migrate within the disc and settle in a thin layer. The creation of a narrow, dense layer of dust is an important stage in the process of planet formation. In this dense region, dust grains clump together to form pebbles and eventually planets themselves.

In addition to the behaviour of dust grains, the Webb, Hubble, and ALMA images reveal several distinct structures that are nested within one another. Emerging at a 90-degree angle from the narrow central disc is a high-velocity jet of gas. The narrow jet is surrounded by a wider, cone-shaped outflow. Enclosing the conical outflow is a wide nebula that reflects the light from the young star that is embedded within the disc. Together, these data reveal HH 30 to be a dynamic place, where tiny dust grains and massive jets alike play a role in the formation of new planets.

The annotated verision of this image can be seen here.

Source: ESA/Webb/potm

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Links

• Science paper
• Hubble, Webb NIRCam and MIRI, and ALMA images of HH 30
• Annotated image of HH 30’s features
• Image on ESA website

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Close look at a local galaxy

NGC 2566

An oval-shaped spiral galaxy, seen close-up. Its core is a compact, pale spot that glows brightly, filling the disc with bluish light. Faint strands of pale reddish dust swirl out from the core to the far sides of the disc. They each join up with an arm of thick, cloudy, red dust with brighter orange patches, that follows the edge of the disc around to the opposite end and a little off the galaxy. ESA/Webb, NASA & CSA, A. Leroy

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The galaxy filling the frame in this NASA/ESA/CSA James Webb Space Telescope Picture of the Month is NGC 2566, a spiral galaxy located in the constellation Puppis. The image combines observations from two of Webb’s instruments, the Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI), to show off NGC 2566’s well-defined spiral arms, long central bar and delicate tracery of gas, dust and stars.

At 76 million light-years away, NGC 2566 is considered a nearby galaxy, making it an excellent target for studying fine details like star clusters and gas clouds. The new Webb images of NGC 2566 were collected as part of an observing programme (#3707) dedicated to understanding the connections between stars, gas and dust in nearby star-forming galaxies. NGC 2566 is just one of the 55 galaxies in the local Universe examined by Webb for this programme.

The mid-infrared wavelengths captured by MIRI highlight NGC 2566’s warm interstellar dust, including complex, sooty molecules called polycyclic aromatic hydrocarbons. The near-infrared NIRCam data give a detailed view of the galaxy’s stars, even those that are deeply embedded within clouds of gas. The NIRCam data also capture some of the light from the hydrocarbon molecules.

To gain a full understanding of the star-formation process in nearby galaxies, astronomers will combine Webb data with observations from other telescopes. At the long-wavelength end of the electromagnetic spectrum, the 66 radio dishes of the Atacama Large Millimeter/submillimeter Array (ALMA) provide a detailed view of the cold, turbulent clouds where stars are born. The NASA/ESA Hubble Space Telescope has also cast its gaze on NGC 2566, and a new Hubble image of this galaxy was released earlier this week. The Hubble data will help researchers take a census of the stars in nearby galaxies, especially the young stars that are bright at the ultraviolet and visible wavelengths to which Hubble is sensitive. Together, the Webb, Hubble and ALMA data provide a rich view of the cold gas, warm dust and brilliant stars in NGC 2566.

The Webb data are part of a Treasury programme, which means that the data may help answer multiple important questions about our Universe. Treasury data are available for use by scientists and the public without a waiting period, amplifying the scientific impact and allowing exploration to begin immediately.

Source: ESA/Webb/potm

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Links

• Webb's MIRI image of NGC 2566
• Slider Tool: Webb and Hubble's views of NGC 2566
• Pan video: NGC 2566 (Webb NIRCam + MIRI image)
• Pan video: NGC 2566 (Webb MIRI image)
• Transition video: Hubble and Webb's views of NGC 2566

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Catching the edge of the Phantom Galaxy (NIRCam and MIRI image)

M74 and NGC 628 (Phantom Galaxy)

A large spiral galaxy takes up the entirety of the image. The core is mostly bright white, but there are also swirling, detailed structures that resemble water circling a drain. There is small white and pale blue light that emanates from stars and dust at the core’s centre, but it is tightly limited to the core. The rings feature colours of deep red and orange and highlight filaments of dust around cavernous black bubbles.

In August 2022, to mark the launch of the Picture of the Month series, ESA/Webb published a stunning image of the Phantom Galaxy (also known as M74 and NGC 628). Now, this series is revisiting the target to feature new data on this iconic spiral galaxy.

M74 resides around 32 million light-years away from Earth in the constellation Pisces, and lies almost face-on to Earth. This, coupled with its well-defined spiral arms, makes it a favourite target for astronomers studying the origin and structure of galactic spirals.

This image features data from two of Webb’s instruments: MIRI (Mid-InfraRed Instrument) and NIRCam (Near-InfraRed Camera). Observations in the infrared reveal the galaxy’s creeping tendrils of gas, dust and stars. In this image the dark red regions trace the filamentary warm dust permeating the galaxy. The red regions show the reprocessed light from complex molecules forming on dust grains, while orange and yellow colours reveal the regions of gas ionised by the recently formed star clusters. Stellar feedback has a dramatic effect on the medium within the galaxy and creates a complex network of bright knots as well as cavernous black bubbles. The lack of gas in the nuclear region of this galaxy also provides an unobscured view of the nuclear star cluster at the galaxy's centre. M74 is a particular class of spiral galaxy known as a ‘grand design spiral’, meaning that its spiral arms are prominent and well-defined, unlike the patchy and ragged structure seen in some spiral galaxies.

M74 was observed by Webb as part of a series of observations collectively entitled Feedback in Emerging extrAgalactic Star clusTers, or FEAST (PI: A. Adamo). Many other targets of the FEAST programme, including NGC 4449, M51, and M83, were the subjects of previous ESA/Webb Picture of the Month images in 2023 and 2024. The FEAST observations were designed to shed light on the interplay between stellar feedback and star formation in environments outside the Milky Way galaxy. Stellar feedback is the term used to describe the outpouring of energy from stars into the environments which form them, and is a process that contributes significantly to determining the rates at which stars form. Understanding stellar feedback is vital for building accurate universal models of star formation.

The new Webb data obtained by the FEAST team has allowed scientists to look at the stellar nurseries in galaxies that are many light years away. Astronomers are learning how other galaxies are forming stars and how stars actively participate to model the galaxy interstellar medium. They have found that newly born stars slowly carve they gas and dust nurseries modifying the morphological appearance and essentially destructing them, as Webb has shown that this evolution is connected with star clusters. Furthermore, the team has concluded from their studies that the spiral arms captured by the extended coverage of the FEAST programme are the places where stars are forming more actively in the galaxy. The brighter and larger complexes of stellar nurseries are in the spiral arms fully captured by the new Webb data. The telescope is now revealing the map of hydrogen emission lines in the near-infrared. These lines are less affected than the dusts and reveals the places where new massive stars have just formed.

Links

• M74 (NIRCam image)
• Pan video: NIRCam and MIRI
• Pan video: NIRCam
• Video transitoning between images
• Science paper (A. Pedrini et al.)
• Science paper (B. Gregg et al.)

Source: ESA/Webb/potm

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The exotic stellar population of Westerlund 1

Westerlund 1

A dense cluster of bright stars, each with six large and two small diffraction spikes, due to the telescope’s optics. They have a variety of sizes depending on their brightness and distance from us in the cluster, and different colours reflecting different types of star. Patches of billowing red gas can be seen in and around the cluster, lit up by the stars. Small stars in the cluster blend into a background of distant stars and galaxies on black. Credit: ESA/Webb, NASA & CSA, M. Zamani (ESA/Webb), M. G. Guarcello (INAF-OAPA) and the EWOCS team

The open cluster Westerlund 1, showcased in this new Webb Picture of the Month, is located roughly 12 000 light-years away in the southern constellation Ara (the Altar) where it resides behind a huge interstellar cloud of gas and dust. It was discovered in 1961 from Australia by Swedish astronomer Bengt Westerlund. Westerlund 1 is an incomparable natural laboratory for the study of extreme stellar physics, helping astronomers to find out how the most massive stars in our Galaxy live and die.

The unique draw of Westerlund 1 is its large, dense, and diverse population of massive stars, which has no counterpart in other known Milky Way galaxy clusters in terms of the number of stars and the richness of spectral types and evolutionary phases. All stars identified in this cluster are evolved and very massive, spanning the full range of stellar classifications including Wolf-Rayet stars, OB supergiants, yellow hypergiants (nearly as bright as a million Suns) and luminous blue variables. Because such stars have a rather short life, Westerlund 1 is very young, astronomically speaking. Astronomers estimate the cluster’s age to be somewhere between 3.5 and 5 million years (its exact age is still a matter of debate), making it a newborn cluster in our galaxy. In the future, it is believed that it will likely evolve from an open cluster into a globular cluster. These are roughly spherical, tightly packed collections of old stars bound together by gravity.

Currently, only a handful of stars form in our galaxy each year, but in the past the situation was different. The Milky Way galaxy used to produce many more stars, likely hitting its peak of churning out dozens or hundreds of stars per year about 10 billion years ago and then gradually declining ever since. Astronomers think that most of this star formation took place in massive clusters of stars, known as “super star clusters”. These are young clusters of stars that contain more than 10,000 times the mass of the Sun, packed into an unbelievably small volume. They represent the most extreme environments in which stars and planets can form. Only a few super star clusters still exist in our galaxy — of which Westerlund 1 is one — but they offer important clues about this earlier era when most of our galaxy’s stars formed.

Westerlund 1 is an impressive example of a super star cluster: it contains hundreds of very massive stars, some shining with a brilliance of almost one million Suns and others two thousand times larger than the Sun (as large as the orbit of Saturn). Indeed, if the Solar System was located at the heart of this remarkable cluster, our sky would be full of hundreds of stars as bright as the full Moon. It appears to be the most massive compact young cluster yet identified in the Milky Way galaxy: astronomers believe that this extreme cluster contains between 50 000 and 100 000 times the mass of the Sun, yet all of its stars are located within a region less than six light-years across. Even so, it is the biggest of these remaining super star clusters in the Milky Way galaxy, and the closest super star cluster to Earth. These qualities make Westerlund 1 an excellent target for studying the impact of a super star cluster’s environment on the formation process of stars and planets, as well as the evolution of stars over a broad range of masses.

The huge population of massive stars in Westerlund 1 suggests that it will have a very significant impact on its surroundings. The cluster contains so many massive stars that in a time span of less than 40 million years, it will be the site of more than 1 500 supernovae. This super star cluster now provides astronomers with a unique perspective towards one of the most extreme environments in the Universe. Westerlund 1 will certainly provide new opportunities in the long-standing quest for more and finer details about how stars, and especially massive stars, form.

This image was captured as part of the The Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) with Webb’s Near-InfraRed Camera (NIRCam). This survey is a dedicated Webb program (GO 1905, PI: M. G. Guarcello) that aims to study star and planet formation and stellar evolution in starburst regions in Westerlund 1 and Westerlund 2, two of the closest super star clusters to the Sun.

With its unparalleled performance in the infrared, Webb offers astronomers the opportunity to unveil the population of low-mass stars in local super star clusters for the first time, and to study the environments around these clusters’ most massive stars. Webb observations of the massive stars in super star clusters can shed light on how feedback (stellar winds, supernovae and other ejected material) from these stars impacts their surrounding environments and the overall star formation process within their parental clouds.

Links

• Westerlund 1 (wide-field view)
• Pan Video: Westerlund 1

Source: ESA/Webb/potm

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SN H0pe

SN H0pe

A two-panel image. In the left panel, dozens of small galaxies are scattered on the black background of space. Just to the left of the center, there is a long, red arc. At its left is a cluster of a few white galaxies that look like a glowing orb. To the right of the center, the red arc and glowing orb of galaxies at the left appear to be mirrored. The curved and distorted galaxy image on the right side is highlighted with a white box. Lines extend from the box’s corners to the right panel, which shows an enlarged view of the curved galaxy. Three faint points of light are circled. Credit: NASA, ESA, CSA, STScI, B. Frye (University of Arizona), R. Windhorst (Arizona State University), S. Cohen (Arizona State University), J. D’Silva (University of Western Australia, Perth), A. Koekemoer (Space Telescope Science Institute), J. Summers (Arizona State University).

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Webb researchers discover lensed supernova, confirm Hubble Tension

Measuring the Hubble constant, the rate at which the Universe is expanding, is an active area of research among astronomers around the world who analyze data from both ground- and space-based observatories. The NASA/ESA/CSA James Webb Space Telescope has already contributed to this ongoing discussion. Earlier this year, astronomers used Webb data containing Cepheid variables and Type Ia supernovae, reliable distance markers to measure the Universe’s expansion rate, to confirm the NASA/ESA Hubble Space Telescope’s previous measurements.

Now, researchers are using an independent method of measurement to further improve the precision of the Hubble constant — gravitationally lensed supernovae. Researchers from different institutions around the world are leading this effort after Webb’s discovery of three points of light in the direction of a distant and densely populated cluster of galaxies.

This is an image from Webb’s NIRCam (Near-Infrared Camera) of the galaxy cluster PLCK G165.7+67.0, also known as G165, on the left shows the magnifying effect a foreground cluster can have on the distant Universe beyond. The foreground cluster is 3.6 billion light-years away from Earth. The zoomed region on the right shows the supernova H0pe triply imaged (labeled with white dashed circles) due to gravitational lensing. 

This field was selected for observation due to its high rate of star formation of more than 300 solar masses per year, an attribute that correlates with higher supernova rates. SN H0pe is one of the most distant Type Ia supernovae observed to date. The measured Hubble constant value matches other measurements in the local Universe, and is somewhat in tension with values obtained when the Universe was young. Future Webb observations in Cycle 3 will improve on the uncertainties.

In this image blue represents light at 0.9, 1.15, and 1.5 microns (F090W + F115W + F150W), green is 2.0 and 2.77 microns (F200W + F277W), and red is 3.56, 4.1, and 4.44 microns (F356W + F410M + F444W).

Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process.

Links

• Blog on STScI website
• Published science paper (1)
  
• Published science paper (2)
  
• Published science paper (3)
  
• Published science paper (4)
  
• Published science paper (5)
  
• Accepted science paper 
  
• Observations programmes (JWST PEARLS)

Source: ESA/Webb/Images

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Jewelled ring

RX J1131-1231

A small image of a galaxy distorted by gravitational lensing into a dim ring. At the top of the ring are three very bright spots with diffraction spikes coming off them, right next to each other: these are copies of a single quasar in the lensed galaxy, duplicated by the gravitational lens. In the centre of the ring, the elliptical galaxy doing the lensing appears as a small blue dot. The background is black and empty. Credit: ESA/Webb, NASA & CSA, A. Nierenberg

This new ESA/Webb Picture of the Month features the gravitational lensing of the quasar known as RX J1131-1231, located roughly 6 billion light-years from Earth in the constellation Crater. It is considered one of the best lensed quasars discovered to date, as the foreground galaxy smears the image of the background quasar into a bright arc and creates four images of the object.

Gravitational lensing, first predicted by Einstein, offers a rare opportunity to study regions close to the black hole in distant quasars, by acting as a natural telescope and magnifying the light from these sources. All matter in the Universe warps the space around itself, with larger masses producing a more pronounced effect. Around very massive objects, such as galaxies, light that passes close by follows this warped space, appearing to bend away from its original path by a clearly visible amount. One of the consequential effects of gravitational lensing is that it can magnify distant astronomical objects, letting astronomers study objects that would otherwise be too faint or far away.

Measurements of the X-ray emission from quasars can provide an indication of how fast the central black hole is spinning, which can provide researchers important clues about how black holes grow over time. For example, if a black hole grows primarily from collisions and mergers between galaxies, it should accumulate material in a stable disc, and the steady supply of new material from the disc should lead to a rapidly spinning black hole. On the other hand, if the black hole grew through many small accretion episodes, it would accumulate material from random directions. Observations have indicated that the black hole in this particular quasar is spinning at over half the speed of light, which suggests that this black hole has grown via mergers, rather than pulling material in from different directions.

This image was captured with Webb’s MIRI (Mid-Infrared Instrument) as part of an observation programme to study dark matter. Dark matter is an invisible form of matter that accounts for most of the Universe's mass. Webb’s observations of quasars are allowing astronomers to probe the nature of dark matter at smaller scales than ever before.

Source:  ESA/Webb/potm

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