New study reveals common pattern of black hole activity shaping nearby galaxies

Image of galaxy NGC 1386, taken with Legacy Surveys
DR10

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Observations of nine nearby galaxies show how active supermassive black holes influence star formation and shock waves across their host galaxies.

Cambridge, MA (September 14, 2026) —A new study of nine nearby galaxies has shown that actively growing supermassive black holes may contribute to star formation, instead preventing star formation, in their host galaxies.

The research, based on observations from the VLT/MUSE instrument, shows that active galactic nuclei (AGN), or bright regions powered by material falling into a supermassive black hole, are associated with star-forming rings or arcs, cone-shaped regions of energized gas, and fast “shocks,” which occur when energy outflows interact with surrounding gas.

The findings, published today in The Astrophysical Journal, give a new perspective on how AGN feedback could influence the growth and evolution of galaxies.

“Once we resolved them, we could see that they not only accrete things, but they also eject things,” said Peixin Zhu, graduate student and astronomer at the Center for Astrophysics. “The injection and accretion are linked with each other.”

The study focused on galaxies whose central black holes are actively accreting, or pulling in, nearby material.

“We’re seeing that black holes are not just consuming material at the centers of galaxies, but they’re actively reshaping their surroundings,” said Lisa Kewley, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, director of the Center, and Zhu’s advisor. “This work helps us understand a complex feedback cycle that plays an important role in galaxy evolution.”

The team used a new three-dimensional diagnostic technique to distinguish among three sources: star formation, radiation from the active black hole and excitation by shocks. Shock excitation occurs when high-speed outflows from the central black hole collide with the interstellar medium.

The galaxy NGC 1386, shown in grayscale on the left and zoomed in to the central region on the right. The colors represent star formation in red, black-hole radiation in blue, and shocks in yellow. Image courtesy Peixin Zhu.

Across the sample, the researchers found that star-forming rings or arcs appeared at distances of about 0.8 to 6 kiloparsecs from the galactic center. Ionized cones of black-hole radiation extended outward from the galaxies’ discs, while central regions dominated by fast shocks often extended perpendicular to those bicones.

The researchers also found evidence for shocks in directions perpendicular to the AGN bicones. Zhu notes that these shocks are broadly consistent with interactions between AGN jets and the interstellar medium, although winds from the active black hole may also contribute, particularly in galaxies with lower-power jets.

“The most interesting phenomena about shocks is that they always go perpendicular to where the black hole’s injected outflows go,” Peixin said. “It is very common, and we see it consistently appearing across the whole nine galaxies.”

The study’s results combined high-resolution observations and detailed theoretical models. The MUSE instrument provided spatially-resolved optical data, while the state-of-the-art theoretical models built by Zhu and her colleagues, astrophysicists Lisa Kewley of the Center for Astrophysics and Ralph Sutherland of the Australian National University, allowed them to compare observations with predictions for black hole activity, star formation and shocks. Chandra X-ray observations also independently supported the researchers’ interpretation.

The results demonstrate that actively growing black holes have a complex cycle of accretion, outflow and interaction with their surrounding galaxies. By separating the effects of black hole radiation, star formation and shocks, the study provides a clearer view of that cycle and its relationship to star formation.

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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eROSITA delivers the most comprehensive census of the high-energy Universe to date

The colour image shows X-ray sources in the western galactic hemisphere of the X-ray sky. The Galactic plane lies horizontally through the centre of the image. Sources in the eROSITA catalogue are plotted with their red, green and blue brightness showing their count rate in soft (0.5-1.0 keV), medium (0.5-1.0 keV) and hard (1.0-2.0 keV), respectively. The sky is plotted using an azimuthal equal area projection. © Jeremy Sanders / MPE

This figure compares the build-up of mass locked in super-massive black holes with the rescaled growth of the stellar population in inactive galaxies over cosmic time. The eROSITA X-ray census traces the fraction of super-massive black hole growth that is directly visible in the soft X-rays, while estimates including obscured sources show that much of the total growth is hidden from this view. The gap implies that roughly 70-90% of super-massive black holes' growth likely occurred in soft X-ray-suppressed phases. The shape similarity of all growth curves supports the claim that accreting super-massive black holes and galaxies evolved in lockstep, growing over broadly similar cosmic epochs. © William Roster / MPE

eROSITA DR2 Representation of the Active Galactic Nuclei (AGN)

This animation shows a representation of the active galactic nuclei (AGN) identified in the DR2 catalogue. Each dot shows a single object, where the distance from the three-dimensional centre increases with the source's redshift, i.e. how far away it is from us. We and our neighbouring objects lie at this centre. Sources at the same distance lie on shells, where the position of the dot on the shell is the position in the sky. The stationary circles, shown horizontally, represent the radii of the shells at redshifts of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5. The animation rotates about the western Galactic hemisphere, highlighting the clumpy nature of structure in the universe.

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To the Point

• Catalogue contents, source types: DR2 lists over 1.9 million pointlike sources such as stars and supermassive black holes, plus about 64,000 extended sources including galaxy clusters and supernova remnants.


• Survey depth, sensitivity: Combining data from three fullsky scans, DR2 detects fainter X-ray fluxes and reveals many previously unknown sources.


• Multiwavelength identification: DR2 links X-ray detections to optical and infrared counterparts using six new catalogues, improving the understanding and classification of cosmic objects.


• Collaboration with SDSS: The release coincides with the Sloan Digital Sky Survey's twentieth data release, enabling 3D mapping of active black holes and studies on their growth across cosmic time.

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Second data release nearly doubles the previously known eROSITA X-ray sources to two million

The German eROSITA Consortium (eROSITA-DE), led by the Max Planck Institute for Extraterrestrial Physics (MPE), has released its second major public dataset, eROSITA Data Release 2 (DR2). The new catalogue comprises close to two million X-ray sources—approximately doubling the number of previously released eROSITA sources in the X-ray sky and marking a major step forward in mapping the high-energy Universe. Built from the first three all-sky scans of the eROSITA telescope aboard the Spectrum-Roentgen-Gamma (SRG) mission, DR2 provides the most comprehensive catalogue of the X-ray Universe currently available to the scientific community. By combining multiple passes over the sky, the release significantly increases the survey depth and reveals large populations of previously undetected sources.

The main DR2 catalogue contains nearly two million X-ray sources detected in the 0.2–2.3 keV band and includes more than 1.9 million point-like sources, primarily stars and actively accreting supermassive black holes, as well as around 64,000 extended sources such as galaxy clusters, nearby galaxies, and supernova remnants. Compared to the first data release, the number of detected sources has roughly doubled.
v A complementary hard-band catalogue adds nearly 15,000 sources detected at higher energies (2.3–5.0 keV), tracing heavily obscured and intrinsically energetic systems that are often missed at softer X-ray energies. Together, these catalogues capture the full diversity of the X-ray sky, from nearby stellar coronae to distant supermassive black holes and massive galaxy clusters. Many of these objects are newly identified in X-rays, while others can now be studied with substantially improved precision.

After the start of operations in December 2019, eROSITA surveyed the entire sky every six months, progressively increasing depth and sensitivity. DR2 combines data collected over the mission’s first 556 days, spanning three full sky surveys (eRASS1–3). By stacking these observations, the survey reaches significantly fainter fluxes than the first release, enabling the large increase in detected sources.

“DR2 is the best inventory of the X-ray sky we have to date and opens the door to robust statistical studies of cosmic populations,” says Miriam E. Ramos-Ceja, Ground Segment Manager of the eROSITA instrument and lead author of the DR2 publication.

Linking X-rays to the broader Universe

To enable physical interpretation, DR2 includes multi-wavelength information that associates the X-ray detections with their most likely optical and infrared counterparts. Based on this information, roughly 88% are extragalactic, dominated by accreting supermassive black holes.

“X-ray detection is only the first step,” explains Mara Salvato, eROSITA spokesperson and chair of the follow-up working group. “By linking X-ray sources to their counterparts at other wavelengths, we can work out what these objects are, where they sit on the cosmic distance ladder, and build clean, well-defined samples on an unprecedented scale.”

A joint milestone with SDSS

The release coincides with the twentieth data release of the Sloan Digital Sky Survey (SDSS), which includes extensive optical spectroscopy of eROSITA-DE sources. Together, these datasets represent the culmination of nearly a decade of collaboration between the German eROSITA Consortium and the SDSS collaboration. By combining SDSS spectroscopy with eROSITA’s X-ray data, researchers can build three-dimensional maps of active black holes across the sky, revealing how these rapidly growing objects are distributed and evolve across cosmic time.

Combining eROSITA’s X-ray catalogue with spectroscopic and photometric redshifts enabled one of the largest and most detailed studies of accreting supermassive black holes to date. These elusive objects formed surprisingly early in the history of the Universe, and eROSITA has provided a new census of their growth at high redshift. “The most luminous black holes at high redshift are like needles in a haystack. Thanks to DR2 we found more needles than expected, suggesting that rapidly growing black holes were more abundant in the early Universe than previously thought” says William Roster, lead author of the corresponding study.

A focused, catalogue-driven release

In contrast to the first public data release, DR2 is a catalogue-focused release. It provides rigorously validated source lists derived from the combined eRASS:3 observations, along with an updated upper-flux-limit service that allows researchers to quantify non-detections across the sky.

The data cover the western Galactic hemisphere, reflecting the agreed data-sharing arrangement between the German and Russian eROSITA consortia. Within this region, DR2 represents the largest and most homogeneous public X-ray dataset currently available.

Enabling the next wave of discoveries

“This is a dataset of unprecedented scale and completeness, now in the hands of the global astronomical community,” says eROSITA Principal Investigator Andrea Merloni. “With nearly 2 million sources, DR2 provides a unique foundation for discoveries ranging from rare objects to large-scale population studies.” MPE Director Kirpal Nandra adds: “eROSITA just set another world record in terms of X-ray source numbers – and it won’t be the last.”

The eROSITA-DE DR2 catalogues, upper-flux-limit server, and full documentation are publicly accessible via the eROSITA-DE Science Data Archive.

Source: Max Planck Institute for Extraterrestrial Physics/Press Releases

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Contacts:

Dr. Miriam Ramos-Ceja
Postdoc High-Energy Astrophysics
Tel: +49 89 30000-3603
Email: mramos@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching

William Roster
PhD-Student High-Energy Astrophysics
Tel: +49 89 30000-3879
Email: wroster@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching

Dr. Andrea Merloni
Senior Scientist High-Energy Astrophysics; PI eROSITA
Tel: +49 89 30000-3893
Email: am@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Mara Salvato
Senior Scientist High-Energy Astrophysics
Tel: +49 89 30000-3815
Email: mara@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching

Dr. Jeremy Sanders
Scientist High-Energy Astrophysics
Tel: +49 89 30000-3340
Email: jsanders@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching

Prof. Dr. Kirpal Nandra
Director of the High-Energy Astrophysics
Tel: +49 89 30000-3401
Email: knandra@mpe.mpg.de
Max-Planck-Institut für extraterrestrische Physik, Garching

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Original publication

1. Ramos-Ceja, M.E., G. Lamer, M. Salvato, A. Merloni, J.S. Sanders et al. The SRG/eROSITA All-Sky Survey DR2: Cumulative X-ray catalogues from the first three surveys and multi-wavelength counterparts in the western Galactic hemisphere
A&A

Source | DOI

2. Roster, W., J. Buchner, M. Salvato, R. Shirley, A. Merloni et al.
Accrete, shine, repeat: AGN X-ray luminosity function
The SRG/eROSITA All-Sky Survey DR2
A & A

Source | DOI

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Further Information

eROSITA website of the MPE

The X-ray sky opens to the world

With about 900 000 distinct sources, the first eROSITA All-Sky Survey (eRASS1) has yielded the largest X-ray catalogue ever published. Based on just the first six months of observations, eROSITA has already detected more sources than had previously been known in the 60-year history of X-ray astronomy.

eROSITA relaxes cosmological tension

February 14, 2024

Results from the first X-ray sky survey resolve the previous inconsistency between competing measurements of the structure of the Universe

Baryons at the Edge: SRG/eROSITA Survey Detects “Missing” Cosmic Gas at the Outskirts of Galaxy Clusters

May 05, 2026
Missing baryons found in galaxy cluster outskirts.
Research uncovers 90% of missing baryonic matter in galaxy cluster outskirts, enhancing cosmic structure understanding.

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A bright X-ray flare from a tidal disruption event

An artist's i,br,brmpression of a tidal disruption event in an active galaxy, in which a star is torn up by the gravitational force from a nearby supermassive.. black hole. Image credit: NASA/CXC/M.Weiss. - Download Image

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This week's significant event is from Maya Nunez, a rising sophomore at California State University, Long Beach, who is doing a Summer Undergraduate Research Fellowship (SURF) with the NuSTAR group at Caltech. Maya is working with Murray Brightman, a NuSTAR Staff Scientist, on transient X-ray sources—that is, X-ray sources that rapidly change in brightness, such as new X-ray sources that suddenly appear in the sky. X-ray transients can be caused by a wide variety of astrophysical processes, including Tidal Disruption Events (TDEs), which occur when a star passes too close to a supermassive black hole and is torn apart. Maya identified a bright X-ray flare from a galaxy hosting an actively accreting supermassive black hole, i.e., an active galaxy. Back in 2019, this galaxy had hosted the bright optical and infrared transient AT2019fdr, whose origin has been under much debate. AT2019fdr is hypothesized to be either a superluminous supernova, a flare from a supermassive black hole, or a TDE. Maya led an approved NuSTAR Director's Discretionary Time proposal to observe this source, and the observations, obtained last week, detected the source in the 3–8 keV NuSTAR energy band. The NuSTAR data provide a late-time X-ray detection from AT2019fdr which, in combination with recent literature, solidifies AT2019fdr’s categorization as a TDE as opposed to a superluminous supernova, since late-time X-ray emission is not common for such supernovae. A flare from a supermassive black hole is also less probable, but not completely ruled out. These new data and findings will expand our understanding of TDEs, particularly TDEs in galaxies with actively accreting supermassive black holes, which have not been as well-studied as TDEs in inactive or quiescent galaxies.

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

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The Environment Around a Supermassive Black Hole

Artist's impression of the innermost regions around a supermassive black hole, showing an accretion disk visually distorted by gravity surrounding the event horizon, and powering an outflow of material. Image credit: CfA/M. Weiss.

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During the past week, NuSTAR observed the nearby active galactic nucleus (AGN) I Zwicky 1 in coordination with the JAXA/ESA/NASA’s XRISM and ESA’s XMM-Newton X-ray observatories. I Zwicky 1 is a unique AGN from which we can learn a lot about the fundamental physics at work as material spirals into a black hole, and the processes by which supermassive black holes grow and are able to have a profound impact on their host galaxies by AGN feedback. In this AGN, we observe X-rays reflecting off the innermost regions of the accretion disk, allowing us to probe the extreme environment just outside the event horizon of the black hole. In addition, I Zwicky 1 is seen to launch an ultrafast outflow: a wind from the inner accretion disk reaching velocities up to 30% of the speed of light. These outflows carry significant energy into their host galaxies and understanding how they are launched is an important step towards understanding AGN/host galaxy feedback. I Zwicky 1 is often seen to launch X-ray flares originating in the corona, and the outflows are seen to evolve in response to these flares. Through these observations, important new insights are expected into the structure of the accretion disk around a rapidly growing black hole, the launching mechanism of the ultrafast outflows, and the connection between these outflows and the innermost regions of the accretion disk and the corona.
Author: Dan Wilkins (Research Assistant Professor, The Ohio State University)

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

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Supermassive black hole accretion flow

An artist’s impression of a supermassive black hole, with intense radiation blasting out across the accretion disk of matter flowing into it. Image credit: NASA/JPL-Caltech. Download Image

A key question in studies of Active Galactic Nuclei (AGN) is the nature of the accretion flow around the supermassive black hole, which is still poorly understood. NGC 4051 offers a rare opportunity to observe this process around a low-mass AGN, which is also one of the brightest of its class. Its unique combination of variability, lower black hole mass, and accessibility to monitoring makes it an ideal laboratory for testing models of the innermost structure of AGN. A critical open question is the role of X-rays in irradiating the accretion disk, and how this effects the total energy observed in the system. For this purpose, NuSTAR's broad energy coverage and sensitivity are ideal for obtaining a high-quality X-ray spectrum. The NuSTAR observation performed last week completes the measurement of the broadband spectral energy distribution for NGC 4051 and is a key component to the 3-month multi-wavelength monitoring campaign of this interesting source that is currently underway.

Author: Marcin Marculewicz (Postdoctoral Fellow, Wayne State University)

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

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NuSTAR & IXPE coordinated observations of Fairall 51

An artist impression of the obscurer surrounding AGN.
Credit: R. Hurt, NASA/JPL-Caltech
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Joint observations by NuSTAR and NASA’s Imaging X-ray Polarimetry Explorer (IXPE) mission last week offer a unique window into the structure of material around the supermassive black hole at the center of the galaxy Fairall 51. The material near the black hole in this active galactic nucleus (AGN) is thought to be oriented at a peculiar angle that reveals both the black hole’s accretion disk and surrounding circum-polar dust. By combining the unique capabilities of NuSTAR and IXPE, a detailed investigation is being made of the radiation from the hot “corona” near the black hole’s accretion disk as well as X-ray photons reflected by the dust structure beyond the disk. These data will constrain how the corona is oriented relative to the putative “torus” of material around the black hole and the perpendicular polar-scattering region identified by ground-based observatories. Ultimately, this coordinated effort will reveal how the small-scale central engine is physically linked to the vast dust structures around it, providing a full picture of the environment near the accreting supermassive black hole.

Author: Chien-Ting Chen, USRA scientist & IXPE science operations at NASA/MSFC

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

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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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Milky Way supermassive black hole archeology

NuSTAR image of the Galactic center region. Sgr A* is the position of supermassive black hole at the center of the Milky Way galaxy. Green dashed ellipses show the areas of giant molecular clouds. The distance from the Bridge to Sgr A* is 200 light years. Credit: Mori 2015.  Download Image

At the center of our Milky Way galaxy is a black hole with a mass more than a million times the mass of the Sun, called Sgr A*. This has been directly confirmed by detailed radio imaging of material close to the black hole by the event horizon telescope as well as the motions of stars in the center of the galaxy effected by the gravitational pull of this supermassive black hole. The low luminosity of Sgr A* indicates that the system is in a relatively quiescent state compared to Active Galactic Nuclei (AGN) in other galaxies which may harbor more massive black holes. However, this has not always been the case, and evidence of higher luminosity in the past is indicated by the increasing X-ray brightness of giant molecular clouds near Sgr A*. Over the past four years observations by NuSTAR of regions close to the center of our galaxy have confirmed that X-ray emission from one of these clouds, called “The Bridge” has been increasing and is likely due to reflection of X-rays from a past Sgr A* outburst approximately 200 years ago. NuSTAR observations last week of The Bridge will add to the detailed investigation of the full profile of this Sgr A* illumination event. Characterizing past Sgr A* outbursts is a necessary step towards understanding the physical mechanisms that triggered major outbursts from a quiescent supermassive black hole, possibly similar to a tidal disruption event seen in other AGN. Observations of The Bridge will continue in 2027, for a proposal selected to be part of cycle 12 of the NuSTAR General Observer program.

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

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Where spiral arms and star formation meet

IC 486

A face-on view of the barred spiral galaxy IC 486, showing a bright, elongated central bar and softly curving, ring-like spiral arms with subtle blue star-forming regions and dark dust lanes, set against a black background dotted with distant galaxies and a few foreground stars.

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A luminous swirl set against the deep black of space, the barred spiral galaxy IC 486 glows with a soft, ethereal light in this new ESA/Hubble Picture of the Month image.

IC 486 lies right on the edge of the constellation Gemini (the Twins), around 380 million light-years from Earth. Classified as a barred spiral galaxy, it features a bright central bar-shaped structure from which its spiral arms unfurl, wrapping around the core in a smooth, almost ring-like pattern.

Hubble’s keen eye reveals subtle variations in colour across the galaxy. The pale, luminous centre is dominated by older stars, while faint bluish regions in the surrounding disc trace pockets of more recent star formation. Wisps of dust thread through the galaxy’s structure, gently obscuring light and tracing regions of increased molecular gas where new stars are likely to form.

At the galaxy’s centre a noticeable white glow outshines the starlight around it. This is light given off by IC 486’s active galactic nucleus (AGN), powered by a supermassive black hole more than 100 million times the mass of the Sun. Every sufficiently large galaxy hosts a supermassive black hole at its centre, but some of these black holes are particularly ravenous, marshalling vast amounts of gas and dust into swirling accretion discs from which they feed. The intense heat generated by the orbiting disc of material generates intense radiation up to and including X-rays, which can outshine the entire rest of the galaxy. In these cases, the galaxy is known as an active galaxy, with an AGN at its centre.

The data used to make this image comes from two separate observing programmes — #17310 (PI: M. J. Koss) and #15444 (PI: A. J. Barth) — with similar aims: to survey nearby active galaxies like IC 486 and record detailed, high-quality images of their central black holes and the stars near the core of the galaxy. By combining Hubble’s sharp imaging with large comprehensive samples, these programmes are enabling detailed comparisons of how stars, gas, dust, and black holes interact in galaxy centres.

A key goal of this work is to understand how galaxies grow by linking their large-scale structures, such as bars and spiral arms, to activity in their nuclei. To achieve this, the research teams are leveraging both expert classifications and citizen science through Galaxy Zoo, with datasets that will ultimately be released to the public. In parallel, the same images are being used to test how well large language models and other machine learning techniques can reproduce or extend human classifications, offering a new way to scale galaxy morphology studies to the largest surveys that are currently being performed with the Euclid telescope.

Beyond IC 486 itself, the image is peppered with distant background galaxies and foreground stars. Some stars appear with characteristic diffraction spikes, while the more diffuse, reddish smudges are far more distant galaxies scattered across the cosmos.

Though it may appear calm and orderly, IC 486 is a dynamic system shaped by gravity and stellar evolution. Over millions of years, its structure will continue to evolve as stars are born, age, and fade, contributing to the ongoing story of galactic life in the Universe.

Source: ESA/Hubble/potm

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Links

• IC 486 (wide-field view)
• Image on ESA website
• Pan video: IC 486
• Pan video: IC 486 (wide-field view)

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NSF–DOE Vera C. Rubin Observatory Launches Real-Time Discovery Machine for Monitoring the Night Sky

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NSF–DOE Rubin Observatory Launches Real-Time Monitoring of the Night Sky

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Capturing the Changing Cosmos: Examples of Alerts from NSF–DOE Rubin Observatory

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Capturando el cosmos cambiante: Ejemplos de Alertas del Observatorio Rubin de NSF–DOE
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Examples of AGN Alerts from NSF–DOE Rubin Observatory

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Ejemplos de Alertas de AGN del Observatorio Rubin de NSF–DOE
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Examples of Solar System Object Alerts from NSF–DOE Rubin Observatory

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Ejemplos de Alertas de Objetos del Sistema Solar del Observatorio Rubin de NSF–DOE
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 Examples of SNe Alerts from NSF–DOE Rubin Observatory

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Ejemplos de Alertas de Supernovas del Observatorio Rubin de NSF–DOE
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Examples of variable stars Alerts from NSF–DOE Rubin Observatory

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Ejemplos de Alertas de Estrellas Variables del Observatorio Rubin de NSF–DOE

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Videos


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Rubin Alerts — Seven million per night


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Alertas de Rubin: Siete millones por noche
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The near-real-time alert system will enable scientists around the world to coordinate follow-up observations like never before

NSF–DOE Rubin Observatory has issued its first scientific alerts, marking a historic milestone in astrophysics. Expected to increase to seven million alerts per night, these first alerts start a new era of dynamic, real-time observation of the night sky.

NSF–DOE Vera C. Rubin Observatory, jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy's Office of Science (DOE/SC), has released its first alerts documenting astronomical events spotted by the observatory. Rubin issued 800,000 alerts the night of 24 February. These alerts called scientists’ attention to new asteroids, exploding stars, and other changes in the night sky. This milestone marks the launch of a system expected to eventually produce up to seven million alerts per night.

Among the first alerts are detections of supernovae, variable stars, active galactic nuclei, and objects whizzing around our Solar System, such as asteroids. The beginning of scientific alerts is one of the last major milestones before Rubin Observatory begins its Legacy Survey of Space and Time (LSST) later this year. During the LSST, Rubin will scan the Southern Hemisphere sky nightly for ten years to precisely capture every visible change using the largest digital camera ever made. These alerts will chronicle the treasure trove of scientific discoveries that Rubin will make through its time-lapse record of the Universe. In the first year of the LSST, Rubin is expected to capture images of more objects than all other optical observatories combined in human history.

“By connecting scientists to a vast and continuous stream of information, NSF–DOE Rubin Observatory will make it possible to follow the Universe’s events as they unfold, from the explosive to the most faint and fleeting,” says Luca Rizzi, a program director for research infrastructure at NSF.

“The discoveries reported in these alerts reflect the power of NSF–DOE Rubin Observatory as a tool for astrophysics and the importance of sustained federal support,” says Kathy Turner, program manager in the High Energy Physics program in the DOE’s Office of Science. “Rubin Observatory’s groundbreaking capabilities are revealing untold astrophysical treasures and expanding scientists’ access to the ever-changing cosmos.”

Rubin’s alerts will power discoveries in many areas of astronomy, astrophysics, and cosmology. While the night sky seems calm and unchanging to the casual viewer, it’s actually alive with motion and transformation. Each alert signals something that has changed in the sky since Rubin last looked — a new source of light, a star that brightened or dimmed, or an object that moved. With Rubin's alerts, scientists will have a greater ability to catch supernovae in their earliest moments, discover and track asteroids to assess potential threats to Earth, and spot rare interstellar objects as they race through the Solar System. Scientists can then use these data to better understand the nature of dark matter, dark energy, and other unknown aspects of the Universe.

“Rubin's alert system was designed to allow anyone to identify interesting astronomical events with enough notice to rapidly obtain time-critical follow-up observations,” says Eric Bellm, Alert Production Pipeline Group Lead for Rubin Data Management from NSF NOIRLab and the University of Washington. “Enabling real-time discovery on 10 terabytes of images nightly has required years of technical innovation in image processing algorithms, databases, and data orchestration. We can’t wait to see the exciting science that comes from these data.”

The near-real-time public nature of Rubin’s alert system enables scientists using other ground and space-based telescopes around the world to coordinate follow-up observations like never before. This collaboration will enable fast and detailed studies of unfolding phenomena.

The first Rubin Observatory alerts distributed to researchers worldwide were generated on the night of 24 February. The alerts contained the flares of new supernovae and the flickers of stars, actively feeding black holes in distant galaxies, and asteroids cruising through our Solar System.

Capturing the Changing Cosmos: Examples of Alerts from NSF–DOE Rubin Observatory

As new images are taken, Rubin Observatory’s sophisticated software automatically compares each one with a template image. The template image, built by combining Rubin’s previous images of the same area in the same filter, is subtracted from the new image, leaving only the changes. Each change triggers an alert within two minutes of image capture. The vast majority of these alerts are supernovae, variable stars, active galactic nuclei, and Solar System objects. The individual images above are “postage stamps” of objects observed by Rubin that changed from one visit to the next. For each of these example alerts, the left shows the template image, the center shows the new image, and the right shows the subtracted, or difference, image. The object of interest for a particular alert is centered in the images. In the case of the supernova above, the bright spots in the upper left corners of the template and new images are the center of the supernova’s host galaxy. The supernova itself — not seen in the template image — is clearly revealed in the center of the difference image. Credit: NSF–DOE Vera C. Rubin Observatory/NOIRLab/SLAC/AURA. Acknowledgement: Alert images with classifications provided by ALeRCE and Lasair.

Located in Chile, Rubin Observatory is jointly operated by NSF NOIRLab and DOE’s SLAC National Accelerator Laboratory. The telescope is equipped with the LSST Camera, the largest digital camera ever built. With 3200 megapixels, Rubin is capable of detecting faint and distant objects in the Universe.

Every 40 seconds during nighttime observations, Rubin captures a new region of the sky. It then sends the data on a seconds-long journey from Chile to the U.S. Data Facility (USDF) at SLAC in California for initial processing. Rubin’s data management system automatically compares it to a template made from previous images of the same region. This comparison allows it to detect the slightest variations. With every change, such as the appearance of a new point of light, an object’s movement, or a change in brightness, the system generates a public alert within a record two-minute interval. With such a large and sensitive camera, and the ability to quickly process historic amounts of data, Rubin can produce up to seven million alerts each night.

“The scale and speed of the alerts are unprecedented,” says Hsin-Fang Chiang, a SLAC software developer leading operations for data processing at the USDF. “After generating hundreds of thousands of test alerts in the last few months, we are now able to say, within minutes, with each image, ‘here is everything’ and ‘go’.”

To interpret the immense flow of data from the Rubin alert stream, scientists rely on a network of intelligent software platforms known as brokers. These systems use machine learning algorithms to filter, sort, and classify the alerts before distributing them to scientific teams and observatories.

“The extraordinary number of alerts that Rubin will produce presents an exciting challenge for both astronomers and software engineers,” explains Tom Matheson, Interim Director of the Community Science and Data Center (CSDC), a Program of NSF NOIRLab, and head of Time-Domain Services, which developed the ANTARES alert broker. “The broker teams have built systems that operate rapidly at scale so that scientists can find all of the objects of interest to them, as well as things we’ve never seen before.”

Brokers also cross-reference alerts with data from multi-wavelength astronomical catalogs. Some of them specialize in specific types of objects and events. These events include early identification of supernovae and Solar System objects. Identifying these events early allows scientists to provide tailored analysis and respond more quickly.

“What’s revolutionary about Rubin is its ability to capture both rapid changes and long-term evolution in the sky,” explains Rosaria Bonito, researcher at the Italian National Institute for Astrophysics (INAF) in Palermo, Italy, and co-chair of the Rubin LSST Transients and Variable Stars (TVS) science collaboration. “Young stars, for example, are highly dynamic and can experience sudden bursts of brightness caused by infalling matter. These events are often short-lived, and scientists can easily miss them without continuous monitoring. Rubin will allow us to detect these changes as they happen right there, right now, and also to track the evolution of stars over a decade.”

Rubin’s alerts are public to the world, meaning anyone — from professional researchers to students and citizen scientists — can access and explore them. Alerts can be accessed through any of the seven official community brokers, as well as two downstream services. These services form an international network that enables prompt, real-time data exploration from anywhere on Earth. Additionally, through collaborations with platforms like Zooniverse, Rubin will empower the global community to classify cosmic events and contribute directly to discovery.

Official brokers for Rubin data are: ALeRCE, AMPEL, ANTARES, Babamul, Fink, Lasair, Pitt-Google, SNAPS, and POI Broker.

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

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More information

NSF–DOE Vera C. Rubin Observatory, funded by the U.S. National Science Foundation and the U.S. Department of Energy’s Office of Science, is a groundbreaking new astronomy and astrophysics observatory on Cerro Pachón in Chile. It is named after astronomer Vera Rubin, who provided the first convincing evidence for the existence of dark matter. Using the largest camera ever built, Rubin will repeatedly scan the sky for 10 years to create an ultra-wide, ultra-high-definition, time-lapse record of our Universe.

NSF–DOE Vera C. Rubin Observatory is a joint initiative of the U.S. National Science Foundation (NSF) and the U.S. Department of Energy’s Office of Science (DOE/SC). Its primary mission is to carry out the Legacy Survey of Space and Time, providing an unprecedented data set for scientific research supported by both agencies. Rubin is operated jointly by NSF NOIRLab and SLAC National Accelerator Laboratory. NSF NOIRLab is managed by the Association of Universities for Research in Astronomy (AURA) and SLAC is operated by Stanford University for the DOE. France provides key support to the construction and operations of Rubin Observatory through contributions from CNRS/IN2P3. Rubin Observatory is privileged to conduct research in Chile and gratefully acknowledges additional contributions from more than 40 international organizations and teams.

The U.S. National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.

The 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.

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 (Kitt Peak) to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community

SLAC National Accelerator Laboratory explores how the Universe works at the biggest, smallest and fastest scales and invents powerful tools used by researchers around the globe. As world leaders in ultrafast science and bold explorers of the physics of the Universe, we forge new ground in understanding our origins and building a healthier and more sustainable future. Our discovery and innovation help develop new materials and chemical processes and open unprecedented views of the cosmos and life’s most delicate machinery. Building on more than 60 years of visionary research, we help shape the future by advancing areas such as quantum technology, scientific computing and the development of next-generation accelerators. SLAC is operated by Stanford University for the U.S. Department of Energy's’ Office of Science.

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Links

• Rubin press release
• SLAC press release
• Vera C. Rubin Observatory website
• Vera C. Rubin Observatory images
• More Rubin images
• Rubin videos
• Check out other NOIRLab Organization Releases

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Contacts:

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

Aaron Groff
Media Relations Lead
SLAC National Accelerator Laboratory
Email: agroff@slac.stanford.edu

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The Black Hole Meetup: EMRIs and IMRIs in the Same Active Galactic Nucleus Disk

llustration of stellar-mass black holes embedded within the accretion disk of a supermassive black hole.
Credit: Caltech/R. Hurt (IPAC)

Title:The Fate of EMRI-IMRI Pairs in Active Galactic Nucleus Accretion Disks: Hydrodynamical and Three-body Simulations

Authors: Peng Peng et al.
First Author’s Institution: Peking University
Status: Published in ApJ

Active galactic nuclei (AGNs) are the extremely luminous central regions of some galaxies, powered by gas accreting onto their supermassive black holes and often outshining the entire galaxy in which they reside. One reason they are so studied in astronomy is that they connect many pieces of physics and astronomy in one cosmic place. This is especially true for AGNs as potential gravitational wave sources. Gravitational waves are observed when two compact objects, usually black holes, orbit each other. Black holes span a massive range of masses, but they are typically categorized into one of three categories: stellar-mass black holes, or sBHs (tens to hundreds of times the mass of the Sun), intermediate-mass black holes or IMBHs (hundreds to thousands of times the mass of the Sun), and supermassive black holes or SMBHs (millions to billions of times the mass of the Sun). AGNs are special because they are among the very few places where black holes across this entire mass spectrum might be found in the same place at the same time. Not only do they host SMBHs at their centers, but their gas disks are ideal nurseries for capturing and growing sBHs and IMBHs.

Current-generation gravitational wave detectors like the LIGO–Virgo–KAGRA (LVK) network can observe stellar-mass to lite-IMBH black hole mergers. Future detectors like the Laser Interferometer Space Antenna (LISA) will be able to observe black holes in the intermediate-mass to supermassive mass range. In addition to the mass range a detector can detect, it is also valuable to know the mass ratio (usually denoted by q) that a detector might detect. Unequal-mass-ratio mergers can tell us a lot about general relativity that more equal-mass mergers cannot because the smaller object orbits the more massive one many times right before the merger, essentially providing a gravitational wave measurement of spacetime around the larger black hole. (See this video for an example of black hole orbits with a large mass ratio, and imagine the spacetime observations around the larger black hole that could be possible with orbits like that.)

One of the most promising advances in gravitational wave detection with LISA will come with the observation of extreme-mass-ratio inspirals (EMRIs), usually defined as involving a smaller black hole that is at least 10,000 times less massive than the massive black hole it orbits (though the exact mass ratio defining an EMRI is a matter of convention and may vary somewhat). In addition, LISA will be able to observe intermediate-mass-ratio inspirals (IMRIs), usually defined as when the smaller black hole is 100–10,000 times less massive than the larger one.

This article uses multiple techniques to address the question of what happens when an AGN disk hosts both an IMBH and an sBH at the same time. The authors began with a hydrodynamic simulation of an AGN gas disk around a 10⁶-solar-mass SMBH. They add a 10³-solar-mass IMBH into the gas disk. Because the IMBH orbits within a gas disk, the gas exerts a force on it, causing its orbit to shrink toward the SMBH (a process called migration). Additionally, the IMBH carves out a path through the gas. Once the IMBH carves out enough of a path in the gas, the authors add an sBH of 20 solar masses into the simulation near the IMBH.

The authors test the sBH outcome for two initial conditions of the gas disk. The first, which I will refer to as “InnerDisk,” is when gas already exists inside the IMBH’s orbit (see Figure 1). The other, which I will refer to as “NoInnerDisk,” is when the simulation begins with gas only outside the IMBHs orbit, with no gas initially between the IMBH and SMBH. In this case, gas crosses the IMBH’s gap after the simulation starts. In the InnerDisk case, the sBH initially gets pushed inward from the presence of the inner gas, but that gas steadily drains into the SMBH and is only partly refilled, so the gas’s push on the sBH weakens over time. In the NoInnerDisk case, the IMBH’s direct pull on the sBH becomes more important. The amount of gas that leaks across the IMBH orbit into the inner disk gradually settles into a steady state that is less dense than the InnerDisk case. With a weaker gas push, the sBH stays closely tied to the IMBH and migrates inward at nearly the same rate. In both setups, the IMBH carves a gap in the gas and keeps moving inward, but the presence and evolution of inner gas chiefly determine how closely the sBH can keep up.

Figure 1: Simulated gas disk around an SMBH with an implanted IMBH at 0 days (left), 10.3 days (middle), and 155 days (right). Brighter orange indicates higher gas density, and darker orange/red indicates lower gas density. An sBH was added at 100 days and is seen in the right panel. These three panels represent the “InnerDisk” scenario. Adapted from Peng et al. 2025

Once the sBH and IMBH migrate close enough to the SMBH, gravitational waves are responsible for more and more of the energy loss and orbital decay of the system compared to the gas. To account for that, once the sBH and IMBH migrate close enough to the SMBH, instead of using a hydrodynamic simulation of a gas disk, the authors switch over to a “three-body problem” solver. Because these are black holes emitting gravitational waves, regular old Newtonian mechanics is insufficient, so they add post-Newtonian terms to correct for this. Additionally, though they no longer model the gas hydrodynamically, they do include terms for a gas “force” acting on the black holes to mimic the gas disk.

Once the IMBH and sBH were in the gravitational regime, their outcomes became much more chaotic. As seen in Figure 2, a slight change in the initial phase angle of the sBH can lead to drastically different consequences for the system. In some cases, the sBH is ejected entirely. In other instances, it merges with the IMBH soon after the simulation begins. Yet in others, it first merges with the SMBH. This leads to one overall message of this article: the orbits of the IMBH and sBH tend to be regular with some gentle variation when they are farther out in the gas disk, but they become highly chaotic once they shrink into the gravitational wave regime closer to the central SMBH.

Figure 2: Post-Newtonian simulation outcomes for different values of sBH initial phase angle from 0 to 2π in increments of 0.02π, while all other initial conditions were kept fixed. Green (binary formation) represents a merger of the IMBH and sBH before reaching the SMBH; red (EMRI after ejection) represents the sBH being ejected from the system, but not before some of its orbits can be observed as an EMRI event; EMRI-IMRI (orange) represents the sBH merging with the SMBH, followed by the merger of the IMBH with the SMBH; and blue (ejection) represents the sBH being ejected from the system entirely before entering a gravitational wave EMRI regime. Credit: Peng et al. 2025

AGN disks may provide a natural setting for interactions among stellar-mass, intermediate-mass, and supermassive black holes. The authors of this article demonstrated that gas can keep an IMBH and an inner sBH migrating together until gravitational waves dominate, after which slight differences in their orbital phases can lead to a wide range of outcomes. While uncertainties remain, this study provides more evidence that LISA could identify. Until LISA flies, continued simulations like this one will help refine the spectrum of EMRIs and IMRIs we can expect to see.

Original astrobite edited by Maggie Verrico

Source: American Astronomical Society/AAS-Nova

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About the author, William Smith:

Bill is a graduate student in the astrophysics program at Vanderbilt University. He studies gravitational wave populations with a focus on how these populations can help inform cosmology as part of the LIGO Scientific Collaboration. Outside of astrophysics, he also enjoys swimming semi-competitively, music and dancing, cooking, and making the academy a better place for people to live and work.

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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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'Reborn' black hole spotted 'erupting like cosmic volcano'

This LOFAR DR2 image of J1007+3540 superimposed over an optical image by Pan-STARRS shows a compact, bright inner jet, indicating the reawakening of what had been a ‘sleeping’ supermassive black hole at the heart of the gigantic radio galaxy. Credit: LOFAR/Pan-STARRS/S. Kumari et al.

Licence type: Attribution (CC BY 4.0)

One of the most vivid portraits of “reborn” black hole activity – likened to the eruption of a “cosmic volcano” spreading almost one million light-years across space – has been captured in a gigantic radio galaxy.

The dramatic scene was uncovered when astronomers spotted the supermassive black hole at the heart of J1007+3540 restarting its jet emission after nearly 100 million years of silence.

Radio images revealed the galaxy locked in a messy, chaotic struggle between the black hole's newly ignited jets and the crushing pressure of the massive galaxy cluster in which it resides.

They have been published today in Monthly Notices of the Royal Astronomical Society after being obtained using highly sensitive radio interferometers – the Low Frequency Array (LOFAR) in the Netherlands and India’s upgraded Giant Metrewave Radio Telescope (uGMRT).

Most galaxies host a supermassive black hole, but only a few produce vast jets of radio-emitting magnetised plasma. J1007+3540 is unique, the international team of researchers behind the new study say, because it shows clear evidence of multiple eruptions – proof that its central engine has turned on, shut down, and restarted after long periods of quiet.

The radio images show a compact, bright inner jet, which lead researcher Shobha Kumari, of Midnapore City College in India, said was the unmistakable sign of the black hole’s recent awakening. Just outside it lies a cocoon of older, faded plasma – leftover debris from the black hole’s past eruptions, distorted and squeezed by the hostile environment around it.

“It’s like watching a cosmic volcano erupt again after ages of calm – except this one is big enough to carve out structures stretching nearly a million light-years across space”, Kumari added.

“This dramatic layering of young jets inside older, exhausted lobes is the signature of an episodic AGN – a galaxy whose central engine keeps turning on and off over cosmic timescales.”

The research was carried out by Kumari and co-authors Dr Sabyasachi Pal, of Midnapore City College, Dr Surajit Paul, associate professor at the Manipal Centre for Natural Sciences in India, and Dr Marek Jamrozy, of Jagiellonian University in Poland.

“J1007+3540 is one of the clearest and most spectacular examples of episodic AGN with jet-cluster interaction, where the surrounding hot gas bends, compresses, and distorts the jets,” Dr Pal said.

The same images with labels showing the compressed northern lobe, curved backflow signature of plasma and the inner jet of the black hole. Credit: LOFAR/Pan-STARRS/S. Kumari et al.

Licence type: Attribution (CC BY 4.0)

J1007+3540 lives inside a massive galaxy cluster filled with extremely hot gas. This environment creates enormous external pressure – far higher than what most radio galaxies experience. As the revived jets push outward, they are bent, squeezed, and distorted by the interaction with the dense medium.

The LOFAR image reveals that the northern lobe is compressed and dramatically distorted, the authors say, showing a curved backflow signature of plasma that seems to be shoved sideways by the surrounding gas.

The uGMRT image also shows that this compressed region has an ultra-steep radio spectrum, meaning the particles there are extremely old and have lost much of their energy – another sign of the cluster’s harsh influence.

The long, faint tail of diffuse emission stretching to the southwest tells an equally dramatic story, the researchers say. It shows that magnetised plasma is being dragged in a large extension through the cluster environment, leaving behind a wispy trail millions of years old. This, they add, suggests the galaxy is not just producing jets, it is also being shaped and sculpted by the powerful environment around it.

Systems such as J1007+3540 are extremely valuable to astronomers. They reveal how black holes turn on and off, how jets evolve over millions of years, and how cluster environments can reshape the entire morphological structure of a radio galaxy.

The combination of restarted activity, giant scale, and strong environmental pressure makes J1007+3540 a useful example of galaxy evolution in action. The authors say it shows that the growth of galaxies is not peaceful or gradual but rather a battle between the explosive power of black holes and the crushing pressure of the environments they live in.

By studying this galaxy, astronomers are gaining rare insight into:

• How often black holes switch between active and quiet phases


• How old radio plasma interacts with hot cluster gas


• How repeated eruptions can transform a galaxy’s surroundings over cosmic time

The research team now plans to use more sensitive, high-resolution observations to zoom even deeper into the core of J1007+3540 and track how the restarted jets propagate through this turbulent environment.

Understanding systems like J1007+3540 helps scientists piece together how galaxies grow, shut down, and awaken again, and how huge cosmic environments can shape, bend, distort, and even suffocate the jets that try to escape from their central engine.

Source: Royal Astronomical Society (RAS)

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Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

Science contacts:

Shobha Kumari
Midnapore City College in India
shobhakumari@mcconline.org.in

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Further information

The paper ‘Probing AGN duty cycle and cluster-driven morphology in a giant episodic radio galaxy’ by S. Kumari et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf2038.

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Notes for editors

About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

Keep up with the RAS on Instagram, Bluesky, LinkedIn, Facebook and YouTube.

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Submitted by Sam Tonkin on Thu, 15/01/2026 - 10:42

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