Cosmic Trio

An AI-generated visualisation of a distant galaxy, containing besides dust, gas and young stars three massive, active black holes (black spheres, not to scale) with bright accretion disks. Other distant galaxies are shown in the background, and few stars in the foreground. © MPE (generated with AI)

Map of the distant galaxy J0148-4214 in ionised hydrogen (Hα). The locations of the three massive black holes are indicated by black circles (not to scale). The most massive and least massive black holes are located in the galaxy centre; a third black hole is located in the galaxy outskirts. © Hannah Übler

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To the Point:

• Researchers have identified three actively accreting supermassive black holes in a distant single galaxy, J0148-4214, for the first time.


• Two of the black holes lie close together in the galaxy’s centre, while a third is located farther out; the discovery was made possible by spatially resolved spectroscopy with JWST/NIRSpec-IFS.


• The finding suggests that mergers and interactions in the early Universe may have played an important role in the rapid growth of supermassive black holes.

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Three Black Holes Discovered in a Young Galaxy for the First Time

An international team led by the Max Planck Institute for Extraterrestrial Physics has identified three actively accreting supermassive black holes in the galaxy J0148-4214. The galaxy is more than 12.5 billion light-years from Earth (at redshift z=5.02), corresponding to roughly 1.2 billion years after the Big Bang. The results are based on spatially resolved spectroscopy obtained with the Near-Infrared Spectrograph in its Integral Field Unit mode (NIRSpec-IFS) aboard the James Webb Space Telescope (JWST).

“This is the first evidence of three active black holes in a single galaxy in the distant Universe,” says Hannah Übler, research group leader at MPE and lead author of the study. Two of them are located in the galactic center and are separated by only 620 light-years in projection. A third black hole is located in the outer region of the galaxy, at a distance of approximately 5500 light-years from the centre. “It suggests that processes in the early Universe were efficient at bringing massive black holes together, setting the stage for the massive black hole mergers we expect to detect with future gravitational wave observatories”, says Übler.

Hydrogen emission as a tracer

The researchers identified the black holes through their spectral fingerprints: the signatures of hydrogen atoms moving at high velocity in the gravitational potential of the black holes. In the central region, the spectrum exhibits a complex structure best explained by two black holes in close proximity. To disentangle the two central sources, the team applied spectro-astrometry, a technique that precisely measures spatial shifts in line emission across the galaxy. This made it possible to determine the positions of the black holes, even though they cannot be spatially resolved as separate point sources. A third black hole was detected in the outer region.

The team also evaluated alternative interpretations—including supernovae, shocks, stellar winds, or very massive stars—but ruled them out through the analysis of other spectral signatures.

Masses and growth

The analysis yields black hole masses of approximately 80 million, 0.6 million, and 2 million suns. The most massive black hole is accreting at a lower rate than the nearby black hole with a mass of 0.6 million suns, which is actively feeding and even exceeding the maximum accretion rate predicted by basic theories of black hole growth (the Eddington limit).

“The JWST data allowed us not only to identify the three black holes, but also to estimate their masses, accretion rates, and the stellar mass of the galaxy,” says Dr. Giovanni Mazzolari, second author of the study and researcher at MPE. “We find a total stellar mass of about 1.3 billion suns, and the black holes represent a significant fraction of that.”

The central black hole pair is expected to merge within the next few hundred million years. “These results are extremely exciting,”, adds Roberto Maiolino, professor at the University of Cambridge and co-author of the study. “They suggest that black hole merging may be an additional, fast route for their rapid growth in the early Universe.”

The third black hole, located off-nucleus, may be the remnant of a previous merger, being displaced from the centre by a gravitational recoil kick, or may currently be migrating inward.

Implications for research

These observations demonstrate that integral field spectroscopy is an important tool for identifying multiple active black holes in distant galaxies. Without the spatially resolved information provided by NIRSpec-IFS, only one of the three black holes would likely have been detected.

The findings provide new insights for understanding the growth of supermassive black holes and their host galaxies. They support the idea that mergers and interactions played an important role in the early Universe and identify this system as a potential precursor to future black hole mergers that could be observed with upcoming gravitational wave facilities such as LISA.

Source: Max Planck Institute for Extraterrestrial Physics/Press Releases

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Contacts:

Dr. Hannah Übler
MPE Lise Meitner Group Leader
Tel: +49 89 30000-3562
Email: hannah@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Giovanni Mazzolari
Postdoc Infrared Astronomy
Tel: +49 89 30000-3389
Email: gmazzolari@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

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Original Publication

Übler, H., G. Mazzolari, R. Maiolino, [...], R. Davies, F. Eisenhauer, N.M. Förster Schreiber, R. Genzel, [...], D. Lutz, [...], T. Shimizu, E. Sturm, L. Tacconi, G. Tozzi et al.

BlackTHUNDER: Evidence of three massive black holes in a 𝒛 ∼ 5 galaxy
A & A

Source

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Further Information

Weighing a Black Hole in the early universe

January 29, 2024

With the upgraded GRAVITY-instrument at the ESO VLTI, a team of astronomers led by the Max Planck Institute for Extraterrestrial Physics has determined the mass of a Black Hole in a galaxy only 2 billion years after the Big Bang. With 300 million solar masses, the black hole is actually under-massive compared to the mass of its host galaxy, indicating that at least for some systems there might be a delay between the growth of the galaxy and its central black hole.

A look deep into the early universe: First infrared interferometry of a quasar at redshift 4

New GRAVITY+ and ERIS observations uncover surprising black hole properties and powerful gas outflows in the early cosmos.

Star dancing around supermassive black hole confirms Einstein

April 16, 2020
Observations led by the MPE have revealed for the first time that a star orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s general theory of relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by Newton's theory of gravity.

Webb detects most distant black hole merger to date

An international team of astronomers have used the NASA/ESA/CSA James Webb Space Telescope to find evidence for an ongoing merger of two galaxies and their massive black holes when the Universe was only 740 million years old.

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Scientists Release Biggest 2D Map of the Universe

PR Image noirlab2620a
Messier 96 as Seen with DESI Legacy Survey

PR Image noirlab2620b
Copeland Septet group of galaxies

PR Image noirlab2620c
Sunset over Kitt Peak National Observatory

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CTIO on the Edge of the World

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Videos


PR Video noirlab2620a
Pan on Messier 96


PR Video noirlab2620b
Zoom into Messier 96

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The new DESI Legacy Imaging Surveys map serves as the foundation for the largest-ever 3D map of the Universe, used to investigate dark energy

Hold on to your telescopes: the DESI Legacy Imaging Surveys team has released the largest-ever 2D map of the Universe. The 5.6-trillion-pixel map contains nearly four billion celestial objects, including stars, galaxies, black holes, and asteroids. The data are available for all to use and are publicly viewable through the Legacy Survey Sky Viewer.

for rare phenomena like gravitational lenses, observe fleeting events like supernovae, and investigate two of physics’ biggest mysteries: dark matter, the invisible substance that accounts for most of the mass in our Universe, and dark energy, the force driving our Universe’s accelerating expansion.

The new map builds on earlier versions from the DESI Legacy Imaging Surveys that have already proved invaluable. To date, more than 1800 science papers have been published referencing the Legacy Surveys’ data.

“It’s part of the fabric of astronomy research now,” says David Schlegel, a co-lead of the Legacy Surveys and scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). “When you're working with astronomical objects today, you often start by pulling up the Legacy Imaging Viewer to see what you’re looking at.”;

Covering roughly 75% of the sky in visible and near-infrared light, the updated map provides a deep view of the extragalactic Universe not blocked by the dust and stars of our own Milky Way. Researchers expect it will remain the most comprehensive 2D map of our Universe for years to come.

More than 160 scientists contributed to data collection for the project, and a team of 20 produced the final dataset released today. It was built by combining 263,407 telescope exposures from three ground-based sky surveys:

• The Dark Energy Camera Legacy Survey (DECaLS), conducted by the 570-megapixel Department of Energy-fabricated Dark Energy Camera (DECam), mounted on the U.S. National Science Foundation (NSF) Victor M. Blanco 4-meter Telescope at NSF Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab.
• The Mayall z-band Legacy Survey (MzLS), conducted by the NSF Nicholas U. Mayall 4-meter Telescope at NSF Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab.
• The Beijing-Arizona Sky Survey (BASS) at the University of Arizona’s Steward Observatory, conducted with the UA Bok 2.3-meter Telescope at KPNO and supplemented by years of data from NASA’s Wide-field Infrared Survey Explorer (WISE) satellite mission.

In addition to the extended file collection, the DESI Legacy Surveys’ full catalog of data is made available as a searchable database via the Astro Data Lab at the Community Science and Data Center (CSDC), a Program of NSF NOIRLab. These services are accessible to the entire astronomy community to facilitate data access and analysis.

“Explorations of our Universe always start with images of the night sky. The DESI Imaging Legacy Surveys are just one step in this venerable human tradition,” says Arjun Dey, co-lead of the Legacy Surveys and an astronomer at NSF NOIRLab. “For our team, these data are fundamental to the investigation of the expansion history of the Universe and the formation of our galaxy. But the skies belong to everyone, and this survey gives everyone the chance to marvel at their wonders.”

The DESI Legacy Imaging Surveys were originally conducted to prepare for the Dark Energy Spectroscopic Instrument (DESI) survey. The Legacy Surveys’ 2D map is essentially a deep photograph of the sky; it records where galaxies and stars appear and how bright they appear. This crucial step enables DESI to select objects and measure their light in different wavelengths to determine their distances, building the largest high-resolution 3D map ever made. Scientists use this map to study the way galaxies have clustered at different ages of the Universe to track dark energy over time.

In April 2026, DESI completed its original five-year survey ahead of schedule and with vastly more objects than expected. The early results have shown surprising hints that dark energy’s impact may be weakening over time — a paradigm shift that could potentially shape the predicted fate of our Universe. DESI expects to publish improved results using its first five years of data in 2027 and is continuing observations into 2028.

Beyond supporting DESI, the Legacy Surveys will be a foundational reference for the next generation of telescopes. As new observatories like NSF–DOE Vera C. Rubin Observatory, jointly funded by the NSF and DOE’s Office of Science (DOE/SC), and NASA’s Nancy Grace Roman Space Telescope come online, researchers can compare their observations with one of the deepest and most comprehensive views of the sky ever assembled.

The Legacy Surveys’ data will also help scientists train artificial intelligence tools to analyze petabytes of astronomical data and accelerate new discoveries. It will be among the datasets used in an astrophysics pilot project within the American Science Cloud, part of the DOE’s Genesis Mission.

Source: NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab)/Press Releases

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More information

The DESI Legacy Imaging Surveys are supported by the U.S. Department of Energy’s Office of High Energy Physics; the National Energy Research Scientific Computing Center, a DOE Office of Science user facility; the U.S. National Science Foundation, Division of Astronomical Sciences; and the partner institutions.

DESI is supported by the DOE Office of Science and by the National Energy Research Scientific Computing Center, a DOE Office of Science national user facility. Additional support for DESI is provided by the U.S. National Science Foundation; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the Secretariat of Science, Humanities, Technology and Innovation (SECIHTI) of Mexico; the Ministry of Science and Innovation of Spain; and by the DESI member institutions.

Lawrence Berkeley National Laboratory (Berkeley Lab) is committed to groundbreaking research focused on discovery science and solutions for abundant and reliable energy supplies. The lab’s expertise spans materials, chemistry, physics, biology, earth and environmental science, mathematics, and computing. Researchers from around the world rely on the lab’s world-class scientific facilities for their own pioneering research. Founded in 1931 on the belief that the biggest problems are best addressed by teams, Berkeley Lab and its scientists have been recognized with 17 Nobel Prizes. Berkeley Lab is a multiprogram national laboratory managed by the University of California for the U.S. Department of Energy’s Office of Science.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. 

The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.

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Links

• Berkeley Lab’s press release
• Legacy Survey Sky viewer
• Photos of the Víctor M. Blanco 4-meter Telescope
• Videos of the Víctor M. Blanco 4-meter Telescope
• Photos of DECam
• Images taken by DECam
• Images of Nicholas U. Mayall 4-meter telescope
• Videos of Nicholas U. Mayall 4-meter telescope
• Check out other NOIRLab Organization Releases

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Contacts:

Arjun Dey
Astronomer
NSF NOIRLab
Email: arjun.dey@noirlab.edu

Josie Fenske
Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu

Lauren Biron
Lawrence Berkeley National Laboratory
Science Communication and Media Relations Specialist
Email: LBiron@lbl.gov

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Twisted Physics: Astronomers Solve 30-Year-Old Stellar Mystery

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wisted Physics: Astronomers Solve 30-Year-Old Stellar Mystery

This artist's illustration shows the twisted, funnel-shaped magnetic field (represented by white spiral lines) that ALMA detected wrapped around the gas outflow streaming from a young star embedded in the NGC 1333 IRAS 4A. New data revealed this ring-shaped structure in unprecedented detail, confirming a decades-old prediction of how magnetic fields launch and shape powerful jets from young stars. redit: NSF/AUI/NSF NRAO/M. Weiss. Hi-Res File

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ALMA Observations of a Protostars’ Twisted Outflow Finally Shows the Magnetic Fields Scientists Predicted — But Couldn’t Prove

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), of which the U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO) is a partner, have captured the first direct, high-resolution images of a magnetic field wrapped tightly around the outflow of gas streaming away from a forming star — evidence that solves a decades-old puzzle about how young stars sculpt the powerful jets that form them.

The findings, from a research team led by Tao-Chung Ching, a former Jansky Fellow at the NSF NRAO, focus on NGC 1333 IRAS 4A, a young double-star system embedded in the Perseus molecular cloud, roughly 960 light-years from Earth.

An “invisible magnetic funnel” made visible by ALMA

Newborn stars grow by pulling in gas and dust from a surrounding disk of material. As they do, they also blast some of that material back out into space in fast, narrow jets and wider, slower outflows — a process astronomers have long suspected is shaped and powered by magnetic fields twisted into a funnel-like, doughnut shape around the jet.

“For the first time, these ALMA observations have captured this invisible funnel of magnetic fields,” said Ching, “This is exciting because it proves a decades-old theory about how stars, like our own Sun, are born and fire off powerful cosmic jets.”

The team used ALMA’s exceptional resolving power, roughly 30 times sharper than that of earlier telescopes, to measure the faint polarization of carbon monoxide gas radiating from the outflow around IRAS 4A. That polarization signal let the researchers trace the morphology and strength of the magnetic field threading through the outflow at distances of only a few hundred astronomical units (the average distance between the Earth to the Sun) from the young star.

The team found the magnetic field measured a few thousandths of a gauss (modest compared to a household magnet, but immense on the scale of interstellar space) and that it wrapped around the outflow like a coil, running perpendicular to the direction the gas was flowing and matching the outflow’s rotation. That geometry is the signature of a “toroidal” (or donut-shaped) magnetic field, exactly what theoretical models have predicted for decades — but never directly confirmed at this level of detail.

“This study represents the first and most high-resolution observation of milligauss-strength toroidal magnetic fields at a scale of several hundred astronomical units from a protostar,” adds Ching.

“We knew that IRAS 4A was a textbook case: 20 years ago, in a work published in Science in 2006, we found that this region followed the theoretically expected magnetically driven collapse”, says Josep Miquel Girart, co-author and researcher at the Institute of Space Sciences (ICE-CSIC) and the Institute of Space Studies of Catalonia (IEEC).

A new tool for mapping magnetic fields

The team also uncovered an unexpected bonus: a straightforward mathematical relationship, based on the physics principle known as Ampère’s law, linking the twisting of the magnetic field to the electric currents flowing through the gas. Because that relationship follows a predictable, linear pattern, it gives astronomers a new and more direct way to work out the direction of magnetic fields in the clouds of gas and dust where stars are born — a notoriously difficult measurement to make.

Understanding how magnetic fields shape stellar outflows helps astronomers explain a fundamental step in star formation, for how young stars shed excess material and angular momentum so they can continue growing, rather than spinning themselves apart. The same physical process is thought to play out at vastly different scales throughout the Universe, from newborn stars like the one studied here, to the supermassive black holes that power distant galaxies.

Source: National Radio Astronomy Observatory (NRAO)/News

Scientific Paper

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Press Contacts:

Jill Malusky
Sr. Public Information Group Manager and Public Information Officer
Email | Phone

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About ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan, together with NRC (Canada), NSTC (Taiwan), ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile, is located on the Chajnantor plateau in northern Chile. ALMA is operated by ESO, the Associated Universities, Inc./National Radio Astronomy Observatory (AUI/NRAO), and the National Astronomical Observatory of Japan (NAOJ).

About NRAO

The National Radio Astronomy Observatory is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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NASA Telescopes Create Colorful 'Craft' From Nearby Nebula

3 Doradus

Credit: X-ray: NASA/CXC/Ohio State Univ./J. Rodriguez et al; Infrared: NASA/ESA/CSA/STScI; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/P. Edmonds

JPEG (551 kb) - Large JPEG (20.6 MB) - Tiff (518.2 MB) - More Images

A Tour of the Tarantula Nebula - More Videos

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• A new study of the Tarantula Nebula is answering questions about why this star formation region in the Large Magellanic Cloud is losing energy from its center.


• By combining data from Chandra, Hubble and Webb, and Spitzer, researchers identified what has tamed the Tarantula and where the energy has gone.


• This new composite image has layers from three of these telescopes: Chandra (blue), Hubble (green), and Webb (red).


• Scientists have concluded that energy has been lost through leakage of gas, the mixing of hot and cold gas and by conduction of heat.

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Like a collage made of layered sheets of colored cellophane, a vibrant new image layers observations of a famous star-forming nebula from NASA space telescopes. The resulting cosmic “craft” reveals new details about the star formation region known as 30 Doradus, or the Tarantula Nebula.

Located in the Large Magellanic Cloud, a small neighbor galaxy to the Milky Way about 160,000 light-years from Earth, the Tarantula has thousands of young stars embedded in a vibrant honeycomb-like structure of gas and dust.

The new composite image contains X-rays from NASA’s Chandra X-ray Observatory, which has repeatedly observed the Tarantula Nebula over the course of its mission, in the layer that appears in blue. The X-ray data reveals gas blown away by winds from the surfaces of young, massive stars and heated to millions of degrees by shock waves, like sonic booms from supersonic jets.

The red represents infrared data from NASA’s James Webb Space Telescope showing thousands of young stars, plus swaths of cool dust that will provide the ingredients to form new stars and planets. Optical data in the green layer from NASA’s Hubble Space Telescope uncovers hydrogen gas that is warmer than seen with Webb, as well as some individual stars through the nebula.

The composite image shows the full Hubble and Webb images of this region, as well as a large section of the Chandra image, all recently published in a research paper in the Astrophysical Journal. In some regions the blue Chandra layer stands alone, and in others it combines with either the red Webb data or the green Hubble data. In the middle region all three images overlap to provide a holistic view in red, orange, yellow, green, and blue.

Tarantula Nebula (30 Doradus)
Optical + Infrared + X-ray

Previously, astronomers had studied the amount and the impact of energy produced by winds from young, massive stars in the Tarantula Nebula. Scientists expect that much of this energy should heat gas so that it produces X-rays. However, the research paper shows that there is much less X-ray-emitting gas in the nebula than expected. This led researchers to ask: Where has this energy gone and what tamed the Tarantula Nebula?

By studying the data from Chandra, Hubble, and Webb, combined with data from NASA’s retired Spitzer Space Telescope, the team concluded the Tarantula may be losing energy from several sources.

First, up to half of the hot gas is leaking through the shell walls of the gas and dust structures and escaping the nebula. Next, there is stirring and mixing between the cold gas near the shell walls and some of the hot gas, lowering the overall temperature of the gas. Finally, comparisons with computer simulations suggest the Tarantula may be losing energy through conduction. This involves direct physical contact between hot and cooler material, like with a frying pan on a burner, causing the hot and cooler material to equalize in temperature. In the case of the Tarantula Nebula, the hot gas would be conducting heat by being in direct contact with the cooler gas in the shells, especially in the densest regions. This scenario does not necessarily involve mixing the hot and cooler gas.

The combination of these three channels for losing large amounts of energy leads to this colorful and complex display revealed by NASA's telescopes working together.

Tarantula Nebula / 30 Doradus, cropped version. Credit: X-ray: NASA/CXC/Ohio State Univ./J. Rodriguez et al; Infrared: NASA/ESA/CSA/STScI; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/P. Edmonds

The paper describing these results was led by Jennifer Rodriguez of The Ohio State University in Columbus. Additional authors on the paper include Laura Lopez, Ohio State; Lachlan Lancaster, Columbia University in New York City; Anna Rosen, San Diego State University; Omnaraynai Nayak, Space Telescope Science Institute in Baltimore; Sebastian Lopez, Ohio State; Tyler Holland-Ashford, NASA’s Goddard Space Flight Center in Greenbelt, Maryland; and Trinity Webb, Ohio State.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Quick Look: NASA Telescopes Create Colorful 'Craft' From Nearby Nebula

Source: NASA’s Chandra X-ray Observatory

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Visual Description:

This release features three images of the Tarantula Nebula, or 30 Doradus, a star-forming region of the Large Magellanic Cloud. Each image represents a different wavelength of light, presented in a different color. When layered atop one another, like sheets of colored cellophane, they combine to produce a vibrant and informative singular image.

The base layer of the nearly square, combined image, features a blanket of wispy blue clouds against a black backdrop. These clouds represent hot gas observed by NASA's Chandra X-ray Observatory. This layer reveals that gas has been blown from the surfaces of young, massive stars, and heated to millions of degrees by shock waves.

The second layer is a rectangular image cutting diagonally across the cloudy blue square, tilted from our upper left down toward our lower right. This layer features roiling red clouds and tiny, gleaming, red specks. These are swaths of cool, ingredient-rich dust, and scores of young stars. This red layer represents infrared data collected by NASA's James Webb Space Telescope.

The third layer is a tilted square, or diamond-shaped image, with its points touching the edges of the big blue base layer. Here, curling, sweeping tendrils of warm hydrogen gas swirl around the frame in shades of green. This layer represents data captured by NASA's Hubble Space Telescope.

In the center of the combined image, the three translucent layers overlap, resulting in a technicolor marvel; an image of intermingled blue, red, and green clouds that blend to include lively shades of fiery orange, golden yellow, and deep purple.

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Fast Facts for Tarantula Nebula (30 Doradus)

Credit: X-ray: NASA/CXC/Ohio State Univ./J. Rodriguez et al; Infrared: NASA/ESA/CSA/STScI; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/P. Edmonds

Release Date: August 11, 2026
Scale: Image is about 10 arcmin (470 light-years) across.
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 5h 38m 38s | Dec -69° 05´ 42"
Constellation: Dorado
Observation Dates: 54 observations from January 2006 to January 2016
Observation Time: 571 hours (23 days 19 hours 56 minutes)

Obs. ID: 05906, 07263, 07264, 16192-16203, 16442-16449, 16612, 16615-16617, 16621, 16640, 17312-17414, 17486, 17544, 17545, 17555, 17561, 17562, 17602, 17603, 17640-17642, 17660, 18670-18672, 18706, 18720, 18721, 18722, 18729, 18749, 18750

Instrument: ACIS
Also Known As: 30 Doradus
References: Rodriguez, J.A., et al, 2026, ApJ, 998, 318.
Color Code: X-ray: blue; Infrared: red; Optical (H-alpha): green
Distance Estimate: About 160,000 light-years from Earth

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Chemical Fingerprints Reveal Hidden Histories of Massive Stars

Artist’s impression of the “chemical fingerprint” used to trace the binary history of massive stars.
Credit: ESO/M. Kornmesser/H. Jin

The star γ Columbae is part of the Southern constellation of Columba, the Dove. The star has nearly six times the mass of the Sun. Credit: Image from go-astronomy.com

On on 23 February 1987, astronomers spotted one of the brightest supernovae in more than 400 years. Located in the Large Magellanic Cloud, SN 1987A was the nearest supernova explosion observed in centuries and it quickly became the best studied supernova of all time. This composite image combines observations made with ALMA, the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-Ray observatory. Credit: ALMA: ESO/NAOJ/NRAO/A. Angelich; Hubble: NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) and P. Challis (Harvard-Smithsonian Center for Astrophysics); Chandra: NASA/CXC/Penn State/K. Frank et al.

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Many massive stars were once part of binary systems, but their exciting past is often lost – at least it was so far. A new study at the Max Planck Institute for Astrophysics and the University of Bonn has now found a new method to identify stars that once gained mass from a companion – stars that now appear as single objects but carry the chemical scars of their binary youth. Using a unique “chemical fingerprint” – independent of specific evolutionary models – they were able to reconstruct the binary histories of massive stars. The method has already reclassified the well-studied star γ Columbae as a former mass gainer – challenging long-held assumptions about its origin– and offered new insight into the supernova SN 1987A’s progenitor.

More than 70% of massive stars are born in close binary systems, where gravitational tugs and mass transfer between companions dramatically alter their evolution. Yet, once the interaction ends – whether through mass transfer, merger, or the supernova explosion of one partner – the surviving star often appears as a solitary object, hiding its turbulent past. For decades, astronomers have struggled to detect these hidden histories.

Now, the new study has cracked the code. The key lies in the surface abundances of elements like carbon, nitrogen, oxygen, and helium. When a massive star accretes material from its companion, it ingests matter from the donor star both from its pristine outer layers and from its core that has been processed by nuclear fusion – rich in nitrogen and helium, and depleted in carbon and oxygen. This material mixes into the accretor’s outer layers, leaving behind a distinct chemical signature. Stars that have undergone such mass transfer follow a unique path in a diagnostic “CNO abundance diagram” – a plot of nitrogen-to-carbon and nitrogen-to-oxygen ratios. While most stars fall along one line, mass gainers form a distinct, previously unrecognized branch, clearly separated from single stars and mass donors.

“We’ve found that the surface chemistry of massive stars is not just a byproduct of their evolution – it’s a record of their story,” explains Harim Jin from the Max-Planck-Institut für Astrophysik, lead author of the study. “For the first time, we can read that story in detail, even when the stars appear alone in the sky.”

This “chemical fingerprint” is a powerful forensic tool. The researchers developed a simple, model-independent analytical framework that allows astronomers to quantify the amount and composition of the accreted material based solely on observed surface abundances. This enables them to reconstruct the initial binary configuration: the masses of the original stars and the efficiency of mass transfer.

“This method gives us a direct window into the hidden lives of stars,” Jin adds. “It’s like finding a fingerprint at a crime scene – once you know what to look for, you can reconstruct the entire sequence of events, even if the original suspects are long gone.”

The method has already yielded surprising results. The star γ Columbae, long thought to be a rare “stripped” star that revealed its core after losing its outer layers, turns out to be a former mass gainer. Its surface chemistry – high nitrogen-to-carbon ratio, moderate nitrogen-to-oxygen ratio, and helium enrichment – matches the predicted signature of a star that accreted material from a massive companion. This reclassification not only reshapes our understanding of γ Columbae but also suggests that many stars previously thought to be stripped may actually be mass gainers.

The implications go far beyond individual stars. The method can be applied to a wide range of massive stars, including runaway stars, supergiants, and even the progenitors of supernovae. It also offers a new way to test theories of binary evolution, particularly the poorly understood physics of mass transfer and angular momentum loss. By comparing observed chemical fingerprints with theoretical models, astronomers can now directly probe the efficiency and stability of mass transfer – long-standing uncertainties in stellar astrophysics.

Moreover, the technique extends to stellar mergers, and has been applied to the famous Supernova 1987A, which is long thought to originate from a merger product. “We can now confidently reconstruct the masses of both stars before the merger” explains co-author Norbert Langer from the University of Bonn, “and demonstrate that a significant amount of mass was ejected during the merger process.".

With ongoing large-scale surveys like WEAVE and 4MOST expected to provide precise data on thousands of massive stars, this new method is poised to transform our understanding of stellar evolution. It turns the surface of a star into a time capsule – revealing not just its current state, but the dramatic, often violent, history of its binary past.

Source: Max Planck Institute for Astrophysics/Press Releases

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Contact:

Dr Harim Jin
Jin, Harim
Postdoc
Email: jin@MPA-Garching.MPG.DE

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Original publication

Harim Jin, Norbert Langer
Chemical fingerprints of binary mass transfer in massive stars
Nature Astronomy, 12 August 2026

DOI

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'Little red dots' may be pulsating monster stars that created early-universe black holes, study finds

This image, created by the researchers, shows distinct layers representing the "shell" produced by massive stars that could be the source of the light we detect called little red dots. It also shows the scale of a supermassive star in relation to massive stars. Credit: Devesh Nandal

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New study accounts for three of the LRDs’ observed properties, getting us closer than any previous work to understanding the mysterious space objects

Cambridge, MA (August 5, 2026)—Astronomers have speculated about the mysterious “little red dots” seen through the James Webb Space Telescope’s images of the early universe: they could be galaxies, black holes, quasi-stars, starbursts...or something else entirely.

Now, in a new study, researchers show that a particular type of star, called a supermassive star, can account for the LRDs' surprising characteristics, including their unusual spectra, their compact appearance in the sky and their abundance of nitrogen.

“To my knowledge, it is the first model that can explain so many of the observed properties at once, from the spectra to the morphology to the chemical signatures,” said Devesh Nandal of the Harvard College Observatory, part of the Center for Astrophysics. “Even competing scenarios are now invoking supermassive stars as the central engine.”

The LRDs are compact, red, and extremely bright sources of light, and whatever is emitting the light existed when the universe was less than a billion years old. Their spectrum of light shows hydrogen occurring in ways that the current astronomical models of young galaxies or ordinary active galactic nuclei can’t explain.

But many observed LRDs don’t have the strong X‑ray or radio emission that astronomers would expect from a growing supermassive black hole.

“Little red dots are mysterious because they combine clues that do not usually fit together,” said Nandal. “They seem to be telling us that something very luminous is hidden inside dense gas.”

In earlier work, Nandal and collaborators showed that monster stars with masses around 100,000 times that of the Sun can reproduce key spectra very much like LRDs, including unusual hydrogen patterns.

The new study looks at whether those stars can also create the dense “cocoons” of gas that make LRDs look so compact in James Webb images.

The researchers tracked the lifespans and evolution of some known monster stars and analyzed how they appear through our telescopes to blink and lose mass. They found that these stars don’t lose mass late in their life like many stars do. Instead, they undergo discrete, powerful pulsation episodes that the researchers call “strange‑mode.” This unusual behavior ejects shell-like shapes of gas.

“The spectrum and the morphology are two sides of the same physical problem,” said Nandal. “The spectrum tells us what kind of source is producing the light and how that light is processed, while the shape tells us where the surrounding material is and how compact it must be.”

Based on their models, the researchers show that a single supermassive star can create both the spectral signatures and the compact gas shell seen in LRDs.

The researchers note that ejected material is mainly hydrogen and helium, but also contains nitrogen. Observations of LRDs are beginning to reveal similar nitrogen‑rich spectra, which are another piece of evidence for their giant star theory.

After its last ejection, these stars continue to evolve until they undergo direct collapse, forming a seed of a supermassive black hole.

“What I find most fascinating is that this result brings together many independent clues in one physical picture,” said Nandal.

The team’s next goal is to turn these properties into full predictions for the detailed spectra of LRDs, so that James Webb observations can directly test their theory.

Source: Harvard-Smithsonian Center for Astrophysics (CfA)/News

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About the Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory designed to ask, and ultimately answer, humanity’s greatest unresolved questions about the universe. )

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Lion Nebula Roars to Life With NASA’s Webb

Lion Nebula (NIRCam and MIRI Image)

NASA’s James Webb Space Telescope imaged the planetary nebula NGC 2392, the Lion Nebula, using the observatory’s NIRCam and MIRI instruments. The central star’s remains are responsible for the nebula’s structure, including a lion face-shaped bubble of ionized gas and dust “mane.” Credit Image: NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI)

Lion Nebula (MIRI Image)

NASA’s James Webb Space Telescope’s mid-infrared image of planetary nebula NGC 2392, nicknamed the Lion Nebula, highlights the varying dust structures. Some dust is being destroyed by the dying central star’s radiation, while some dust filaments manage to survive. Credit Image: NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI)

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Observing across the starry “plains” of space, NASA’s James Webb Space Telescope has taken new images of NGC 2392, nicknamed the Lion Nebula. NASA’s Hubble Space Telescope previously viewed this planetary nebula in 2000, imaging the lion face-shaped target in visible light and revealing features such as the “mane” of hazy, comet-shaped objects. Now Webb has captured a clearer, more detailed view of the Lion Nebula due to its high-resolution imaging.

At first glance the nebula’s overall structure in Webb’s infrared images, with both the NIRCam (Near Infrared Camera) and MIRI (Mid Infrared Instrument) instruments, may look quite similar to Hubble’s earlier visible-light view. However, Webb’s infrared vision highlights features like compact clumps of dust and a haze of ionized gas. It’s taken several thousand years for this collection of gas and dust to reach its current shape, and the nebula’s components continue to be altered.

The source of these constant changes and the reason for the Lion Nebula’s distinct appearance is located at the center: the remains of a dying star. Though it looks like the button nose of the lion, its energy and radiation are powering the intricate structures seen here.

Massive stars undergo supernova explosions at the end of their lives, but these kinds of events are few and far in between. Most of the universe’s stars have lower masses, like the one belonging to NGC 2392. When a lower-mass star can no longer sustain itself with nuclear reactions in its core, the star becomes unstable and pulsates, losing its mass by shedding its outer layers, which then turn into shells of gas and dust called a planetary nebula. (Stars at this life stage are responsible for producing much of the universe’s observable dust.) The star’s radiation drives the ejected material away, leaving behind the very hot stellar core, also known as a white dwarf.

In the Lion Nebula’s case, the death of the oxygen-rich central star has left behind a white dwarf that is “cooking” everything from the inside and producing a bubble of ionized gas as it does. The gas bubble, which forms the lion’s face, is expanding over time and destroying dust that is in its path. Understanding why the swept-up gas has a complex structure of rings and shells, a common feature in planetary nebulae, is an ongoing endeavor.

The mane of the lion is the interior of a dust shell that is being illuminated by the white dwarf at the center. The tufts of hair, which look like cometary tails of material, are compact clumps of dust that have survived the stellar core’s radiation and protect the material that lies behind them.

Webb’s imagery “freezes” this planetary nebula in time, though the star’s death, and its tumultuous effects, go on. NGC 2392 will continue to undergo changes as its gas and dust migrate away from the stellar core. Astronomers estimate the lion will eventually disperse in approximately 10,000 years — a relatively short period in astronomical terms.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing 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).

Source: NASA's James Webb Space Telescope/News

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Hunting for the Source of Superfast Electrons with NuSTAR

A multi-wavelength image of the supernova remnant shell of PWN G0.9+0.1, combining high-energy X-ray data from NuSTAR (green), low-energy X-ray data from XMM-Newton (blue), and radio data from MeeRKAT (red). The pulsar remnant of the supernova explosion is the compact X-ray source at the center of the image, while the brighter compact X-ray source to the lower right is unrelated. The radio data shows the shape of the nebula, as well as the fainter outer shell of the supernova remnant. Image credit: Brunelli et al. (2026)/MeerKAT (Heywood et al. 2022)/H. Earnshaw. Download Image

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Earth is continuously bombarded with cosmic rays—particles such as protons and electrons flying through space incredibly fast. The faster a particle travels, the more energy it has, and a small fraction of these cosmic rays have energies greater than a petaelectronvolt, or PeV. This is about the energy of a buzzing housefly, which might not seem like a lot, but it's all contained in one single, incredibly energetic electron moving at mind-blowing, relativistic speed. Accelerating electrons to such extreme speeds takes a cosmic-scale particle accelerator, which astronomers have nicknamed a 'PeVatron'. But what kind of astronomical source could be capable of such a feat?

Pulsar wind nebulae are some of the most fascinating objects in our Galaxy. They are created in the aftermath of a supernova, the explosion of a massive star at the end of its life when it has exhausted its fuel supply. Supernovae usually leave behind a compact remnant, either a black hole or a neutron star, and a rapidly spinning neutron star can appear to pulse, almost like a light house. This inspired the term “pulsar” to describe such remnants. A rapidly spinning pulsar will illuminate the extended bubble of outflowing material from the explosion, producing highly energetic particles accelerated by the strong magnetic field of the nebula. Pulsar wind nebulae can be detected at X-ray and even gamma-ray energies, making these cosmic powerhouses ideal candidates in the hunt for PeVatrons.

Dr. Kaya Mori of Columbia University is leading a large program with NASA’s NuSTAR X-ray satellite to hunt for PeVatrons in pulsar wind nebulae in our Galaxy. NuSTAR is the first satellite to focus high-energy X-ray photons, making it the most sensitive instrument for studying the Universe at X-ray energies above 10 keV, roughly the energy of X-ray machines you'd find at a hospital. One of the nebulae studied is this program is G0.9+0.1, a young supernova remnant in the Galactic Center. In a recent paper published in the Astrophysical Journal led by PhD student Giulia Brunelli at INAF Bologna, high-energy X-ray data from NuSTAR is combined with multiwavelength data from radio and gamma-ray observatories. Modeling these observations, the team determined that this pulsar wind nebula is very young—about 2,200 years old—and capable of accelerating electrons up to 2 PeV. This makes G0.9+0.1 a compelling PeVatron candidate, meaning that it—and perhaps other pulsar wind nebulae churning away in the Galactic Center—may be one of the objects responsible for some of the highest-energy particles arriving at Earth.

Source: NASA's Nuclear Spectroscopic Telescope Array (NuSTAR)/Press Realeases

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A Middle-Aged Supernova Remnant Stays Energetic

Combined X-ray observations of the Puppis A supernova remnant from Chandra and XMM-Newton, showing the shock waves of material expanding out into space. Low-energy X-rays are shown in red, medium-energy X-rays are in green and higher energy X-rays are colored blue. NuSTAR observations will be able to probe higher energies still. Image credit: NASA/CXC/IAFE/G.Dubner et al & ESA/XMM-Newton. Download Image

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During the past week, NuSTAR observed the supernova remnant Puppis A, the expanding debris of a stellar explosion that occurred roughly 4,000 years ago. While supernova remnants are widely believed to be the primary accelerators of Galactic cosmic rays, clear evidence for ongoing production of very high-energy particles is usually found only in much younger systems. Recent X-ray observations, however, revealed a hint of an unexpected enhancement of hard X-rays in the eastern region of Puppis A, where the blast wave is interacting with dense interstellar clouds. These observations suggest the presence of a reflected shock — a secondary shock wave generated when the expanding remnant encounters surrounding material — that may be accelerating particles even today. The primary goal of the NuSTAR observation is to determine whether the newly discovered hard X-rays are produced by freshly accelerated electrons. If confirmed, Puppis A would provide one of the clearest and most remarkable examples of active particle acceleration in middle-aged supernova remnants. Given its age of about 4,000 years, finding signs of fresh acceleration would demonstrate that supernova remnants can continue to energize particles far longer than traditionally expected, offering a rare opportunity to study how cosmic-ray factories evolve long after the original stellar explosion. By measuring the high-energy X-ray spectrum up to energies of tens of keV, NuSTAR will determine how these particles are accelerated, estimate the maximum energies they can reach, and probe the magnetic environment within the shock. These measurements will provide new insight into the long-term evolution of shock acceleration and the origin of cosmic rays in our Galaxy.

Author: Hiromasa Suzuki (Assistant Professor, University of Miyazaki, Japan)

Source: NASA's Nuclear Spectroscopic Telescope Array (NuSTAR)/Weekly Highlights

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A Trillion Mile Cosmic Stream of Gas Feeds GW Orionis

This artist's representation highlights the streamer feeding material onto the protoplanetary disk, GW Ori, creating misaligned dust rings. Credit: NSF/AUI/NSF NRAO/B.Saxton. Hi-Res File

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ALMA Captures Streamer in Action Deep Within a Complex Triple-Disk System

The Triple Stars and Tilted Disks of GW Orionis

These new ALMA observations focus on GW Orionis, a very young system located about 1,300 light-years away in the Orion constellation, that hosts three stars encircled by multiple rings of planet-forming material. The rings in this system are famously tilted at different angles instead of lying in a single flat plane, making GW Orionis a natural laboratory for studying the formation of unusual planetary architecture.

A team led by Maria Galloway-Sprietsma, a PhD candidate at the University of Florida, measured how the streamer is moving and compared its motion, known as its angular momentum, to the orientations of the system’s rings. They found that the streamer’s trajectory lines up closely with the outer dust ring but is strongly misaligned with the inner ring, pointing to a likely cause-and-effect connection between the infalling material and the outer ring’s tilted state.

“Previous studies of GW Orionis revealed that the system’s inner, middle and outer rings are misaligned, with each ring tilted at a different angle. When our team modeled the infall of this streamer, we found that the angle at which it impacts the disk is closely aligned with the outer ring,” explains Galloway-Sprietsma. For decades, textbook diagrams have shown young planetary systems forming quietly from flat, orderly disks of gas and dust. This new ALMA result supports a more dynamic picture, in which clumpy, turbulent streamers from the surrounding environment can reshape disks late in their evolution and potentially set planets on orbits that are tilted or even opposite to the spin of their host star. ALMA’s Capabilities Proved Best Tool For Research

“None of this would have been possible without ALMA. ALMA has the highest resolution offered for these wavelengths. Archival data allowed astronomers to see these high-resolution dust rings to model their relative misalignments, and now our observations use all three ALMA arrays – the 12-meter, 7-meter, and Total Power – to zoom out and

see the full extent of the streamer, so really the observations with ALMA have been building, year after year,” Galloway-Sprietsma says. ALMA’s unique capabilities allowed Galloway-Sprietsma and her team to dig deeper into the data. “Because ALMA is such a sensitive instrument, we were able to study kinematics of the streamer with the molecular line data,” Galloway-Sprietsma adds. By observing molecular lines of 12CO and 13CO with ALMA , Galloway-Sprietsma and her team found that the total angular momentum of the streamer is much less than that of the GW Orionis disk. This means that the dynamics of this system likely represent the later stages of this infall phenomenon. “The estimated angular momentum of the streamer is less than that of the outer disk, so this would mean that the streamer should not significantly misalign the disk and further. In the past it likely had a greater angular momentum, and that allowed the disk to become misaligned,” points out Jaehan Bae, Assistant Professor Astronomy with the University of Florida, a co-author of the research and Galloway-Sprietsma’s PhD advisor.

Future Research for GW Orionis

Astronomers hope to survey more young systems with streamers to see how common this mechanism is and whether it can explain other puzzling features of known exoplanet systems, such as wild orbital tilts and unusual chemical signatures. Future ALMA observations of GW Orionis will search for shock-tracing molecules, including sulfur-bearing species, to pinpoint exactly where the streamer slams into the disk and how that impact alters the raw material for planet formation.

Source: National Radio Astronomy Observatory (NRAO)/News

Scientific Paper

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About ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Press Contacts:

Jill Malusky
Sr. Public Information Group Manager and Public Information Officer
Email | Phone

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EXCELlent Work, Detectives! Solving the Murder of Star Formation in Galaxies with JWST

This JWST image shows a pair of interacting galaxies, collectively known as Arp 142. The galaxy on the right ("the Penguin") is alight with recent star formation, while the galaxy on the left ("the Egg") contains mostly old stars. Credit: NASA, ESA, CSA, STScI

Title: The JWST EXCELS Survey: Insights into the Nature of Quenching at Cosmic Noon
Authors: Maya Skarbinski et al.
First Author’s Institution: Johns Hopkins University
Status: Published in ApJ

How to Quench a Galaxy

Look at an image of the sky taken with a sufficiently sensitive telescope, and you’ll quickly notice that galaxies tend to cluster into two main types: blue spiral galaxies, which have flat disk shapes with a central bulge, and red elliptical galaxies, which look like spherical or elliptical balls of red stars. Blue spiral galaxies can form tens to hundreds of stars every year, while elliptical galaxies have completely stopped forming stars, meaning that some process has to transform star-forming spirals into non-star-forming, or “quiescent,” elliptical galaxies. To form the current population of massive elliptical galaxies, this process had to be common about 2–3 billion years after the Big Bang at “cosmic noon,” the period when star formation in the universe peaked. The processes that “quench” star formation in massive galaxies are still being studied, and one of the best ways to study them is to find galaxies that recently quenched and look for clues about the processes that quenched them.

Post-starburst galaxies are galaxies that have rapidly quenched after a short burst of star formation. Because these galaxies quenched so quickly and so recently, it’s often possible to find signs of whatever quenched them, like the signatures of past galaxy mergers, feedback from supermassive black hole accretion, or the shutoff of gas flowing into the galaxy. Rapid quenching is pretty uncommon now, but it was a much more common way for galaxies to quench at cosmic noon. Understanding post-starburst galaxies at cosmic noon is therefore critical for understanding the formation of massive elliptical galaxies in the local universe.

The Quest for Quenched Galaxies

Today’s article uses data from the JWST Early eXtragalactic Continuum and Emission Line Survey (EXCELS) to identify post-starburst galaxies at cosmic noon and try to determine why they quenched. EXCELS is a spectroscopic survey, so the authors get a spectrum for every galaxy. The spectrum encodes information about the galaxy’s stellar population, including the mass of stars in the galaxy, the number of stars forming every year, and the history of star formation throughout the galaxy’s life.

The authors use a technique called principal component analysis to further divide the sample into young and old post-starbursts. Principal component analysis is a machine-learning technique that learns the most important features of a data set. This technique is used for “dimension reduction,” or reducing the number of data points needed to learn something about the object. A typical spectrum has hundreds or even thousands of data points, which means performing data analysis on a spectrum can be very computationally expensive. Principal component analysis takes these thousands of data points and learns broad patterns that correlate with each other. These patterns are called “supercolors” in the context of spectral data, and they encode things like the overall shape and color of the spectrum as well as the spectral shape around key features (see Figure 1 for a visualization). Since the overall shape, color, and emission/absorption line features of a spectrum come from the galaxy’s stellar population, this method can be used to identify galaxies with lots of star formation a billion years ago but very little star formation today — in other words, post-starburst galaxies.

Figure 1: An example of principal component analysis for sample star-forming (SF), quiescent (Qu), and post-starburst (PSB) galaxy spectra (left-hand side). Principal component analysis simplifies a many-dimensional data set (for example, spectra) into fewer dimensions. In this case, Super-Color 1 measures the overall color of the spectrum (shown on the left-hand side as the slope of the spectra, marked with red lines), while Super-Color 2 measures the shape of the spectrum around 4,000 angstroms (orange box). The authors use principal component analysis to identify post-starburst galaxies for further analysis (right-hand side). Adapted from Skarbinski et al. 2026

The authors apply principal component analysis to the galaxies in their sample and find that 11 of the galaxies in their sample are classified as post-starburst, 9 are quiescent, and 4 still have some star formation. To further analyze the stellar populations of the post-starbursts in their sample, the authors use a program called Bagpipes to fit the galaxies’ spectra. Bagpipes is a spectral energy distribution fitting software, which means that it takes the observed spectrum of a real galaxy and tries to match it to a library of different stellar spectra. By measuring the relative contribution of different kinds of stars (which all have different lifetimes), Bagpipes can compute the likely history of star formation in the galaxy (e.g., when the star formation rate peaked) as well as the present-day properties of the galaxy (things like the mass in stars versus dust and the current star formation rate). The authors use the galaxies’ star formation histories to try to find clues as to how they quenched.

Figure 2: Possible evolutionary tracks in supercolor for two example galaxies as they quench. The galaxy in the top panel quenches quickly and has post-starburst supercolors for about a billion years, while the galaxy in the bottom panel quenches without ever going through the post-starburst phase. The authors use these tracks to determine how important the post-starburst phase is for quenching massive galaxies. Credit: Skarbinski et al. 2026

How Quickly Do Post-Starbursts Quench?

First, the authors measure something called a “quenching timescale,” which they define as the length of time between when the galaxy’s star formation rate peaked and when it fell low enough that the galaxy was quenched. The quenching timescale depends on which process shut down star formation in the galaxy — feedback from black hole accretion or star formation should cause fast quenching, while galaxies that are starved of gas from the intergalactic medium should quench more slowly. The authors find that 15 of their galaxies quenched in under 500 million years, 6 took between 500 million and 1 billion years, and 3 took longer than 1 billion years to quench. The galaxies that had the highest peak star formation rates quenched the fastest, suggesting that feedback from star formation could have played a role in quenching these galaxies.

Next, the authors measure how important the post-starburst phase is to form massive quiescent galaxies. Not all galaxies that quench go through a post-starburst phase; some objects, especially those that quench slowly, will transition directly from star forming to quiescent. The authors use the star formation histories from their spectral energy distribution fits to predict how the galaxies’ supercolors changed after their star formation peaked (Figure 2) and find that six of the nine quiescent galaxies went through a post-starburst phase in the past, while the other three did not. For the objects that went through a post-starburst phase, the median time spent as a post-starburst was around 600 million years.The authors can use this measured “visibility timescale” to constrain whether the post-starburst phase is important for forming massive quiescent galaxies. If the fraction of post-starburst galaxies in a sample is high, that can be for two reasons: either a larger fraction of galaxies will eventually go through a post-starburst phase, or the post-starburst phase is very long, making it easy to find post-starburst galaxies. Using the measured timescale of 600 million years and combining with results from another article, the authors find that 40% of quiescent galaxies likely went through a post-starburst phase; for the more massive end of the sample, this fraction increases to around 73% due to the shorter visibility timescale. This suggests that the post-starburst phase is very important for forming the kind of massive quiescent galaxies we see in the local universe.

While the post-starburst phase is important, the different quenching timescales present across the sample suggest that multiple pathways existed to quench galaxies at cosmic noon, similar to what has been found in less-distant galaxies and at cosmic noon in other samples. This is also supported by the fact that four of the five galaxies with sufficient data show evidence of an actively accreting supermassive black hole that may help shut down star formation in many (but perhaps not all) massive galaxies. While the precise processes that quench massive galaxies are still uncertain, one thing is clear: JWST EXCELS at solving the mystery!

Original astrobite edited by Anavi Uppal.

Source: American Astronomical Society/AAS-Nova

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Editor’s Note: Astrobites is a graduate-student-run organization that digests astrophysical literature for undergraduate students. As part of the partnership between the AAS and astrobites, we occasionally repost astrobites content here at AAS Nova. We hope you enjoy this post from astrobites; the original can be viewed at astrobites.org.

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About the author, Margaret Verrico:

I am a fourth.-year graduate student at the University of Illinois Urbana-Champaign. I study the connection between supermassive black hole transients and their host galaxies. I am also an avid knitter and reader, and I am passionate about opening up STEM opportunities for people of all backgrounds.

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