ALMA pinpoints the radio signature of planetary growth

Multi-frequency imaging of PDS 70 with .a zoom on the forming protoplanet PDS 70c. From left to right are the ALMA bands 4, 7, and 9. PDS70c shines in Bands 4 and 7, ,brbut not in Band 9, which can be attributed to ionized gas emission. Credit: O. Domínguez et al. – N. Lira – ALMA (ESO/NAOJ/NRAO)

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New multi-frequency observations reveal that the growing giant planet PDS 70c shines in radio waves not from dust, but from ionized gas in its environment.

Highlights

• Unprecedented multi-frequency radio observation of a forming planet: ALMA observed PDS 70c in Bands 3, 4, 7, and 9, revealing new details about its environment.
• Not dusty, but gaseous: The radio signal originates from ionized gas, not from the dusty disk astronomers anticipated.
• Likely origin in a circumplanetary disk: The emission most likely comes from the surface of a small disk surrounding the planet, where mass from the environment is deposited.
• Clues to planet and moon formation: These findings present the first radio spectral fingerprint of a circumplanetary environment, offering insights into how giant planets develop and how moons may form.

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have obtained an unprecedented multi-frequency view of a forming planet in the nearby star system PDS 70. The new study, led by postgraduate student MsOriana Domínguez-Jamett (Universidad de Chile) and published in Astronomy & Astrophysics, shows that the planet PDS 70c emits radio signals produced by ionized gas rather than the dusty disk expected around such a young world.

PDS 70, a young star 370 light-years away in the constellation Centaurus, is famous for hosting two directly imaged protoplanets. Among them, PDS 70c is thought to be surrounded by a circumplanetary disk — a disk of gas and dust feeding the planet and possibly forming moons. Until now, the exact origin of its radio emission remained a mystery.

Using new ALMA observations in Bands 4 (145 GHz), 7 (343.5 GHz), and 9 (671 GHz), together with archival Band 3 data (97.5 GHz), the team detected a compact source at the position of PDS 70c in three of the bands. Intriguingly, they found no signal in the highest frequencies (Band 9). This “drop” in brightness challenges the idea that the emission originates solely from thermal dust. Instead, the results are best explained by partially optically thick free-free emission — radio light generated by the collisions of electrons and ions. In simple terms, the radio light from PDS 70c mainly comes from the surface of a small disk surrounding the planet. This gaseous disk shines because its surface is ionized by the impact of infalling material, making it appear as a faint, glowing veil around the young planet.

“Our observations suggest that a standard dusty disk does not surround PDS 70c,” says lead author Oriana Domínguez-Jamett. “Instead, the signal points to ionized gas, possibly heated in shocks as material falls onto the planet’s disk. This means the planet is depleted of dust by at least a factor of a thousand compared to expectations.”

By comparing the spectrum with simple models, the researchers demonstrate that a very low ionization fraction can explain the observed turnover in emission. This marks the first time the radio emission mechanism in a circumplanetary environment has been identified.

“This is a breakthrough in our ability to study how gas giant planets grow and how their moons may form,” adds advisor Simon Casassus (Universidad de Chile). “ALMA can now not only detect circumplanetary disks but also determine what powers their emission.”

“These results highlight ALMA’s unique ability to probe the environment of forming planets,” says John Carpenter, ALMA Observatory Scientist. “By distinguishing between dust and gas emission, we gain a direct view of how young planets gather material and how future moon systems begin to form.”

The findings provide key new constraints on the density, temperature, and ionization state of the material around forming gas giants. They also highlight the unique potential of ALMA to explore the final stages of planet growth.

Additional Information

The results of this study appear in the Astronomy & Astrophysics as "Multi-frequency observations of PDS70c: Radio emission mechanisms in the circumplanetary environment" by O. Domínguez et al.

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 ALMA's construction, commissioning, and operation.

Scientific Paper

Source: ALMA (Atacama Large Millimeter/submillimeter Array)/Press Release

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Yellow and blue, old and new

NGC 6000

An oval-shaped spiral galaxy, of which only the centre and lower half is in frame. Its centre is mainly golden in colour with a white glowing core, while its thick spiral arms are mostly blue, particularly at the outskirts; the colours merge in between. Dark lanes of dust swirl through the centre, blocking some of its light. Stars and distant galaxies can be seen around the edges on a black background.Credit: ESA/Hubble & NASA, A. Filippenko - Acknowledgement: M. H. Özsaraç

Stars of all ages are on display in today’s NASA/ESA Hubble Space Telescope Picture of the Week. This sparkling spiral galaxy is called NGC 6000 and it is located 102 million light-years away in the constellation Scorpius.

This galaxy has a glowing yellow centre and glittering blue outskirts. The colours reflect differences in the average ages, masses and temperatures of the galaxy’s stars. In the heart of the galaxy, the stars tend to be older and smaller. Less massive stars are cooler than more massive stars, and somewhat counterintuitively, cooler stars are redder, while hotter stars are bluer. Farther out along NGC 6000’s spiral arms, brilliant star clusters host young, massive stars that appear distinctly blue.

Hubble collected the data for this image while surveying the sites of recent supernova explosions in nearby galaxies. NGC 6000 has hosted two recent supernovae: SN 2007ch in 2007 and SN 2010as in 2010. Using Hubble’s sensitive detectors, researchers are able to discern the faint glow of supernovae years after the initial explosion. These observations help to constrain the masses of supernova progenitor stars and can indicate if they had any stellar companions.

By zooming in to the right side of the galaxy’s disc in this image, you may see something else yellow and blue: a set of four thin lines. These are an asteroid in our Solar System, which was drifting across Hubble’s field of view as it gazed at NGC 6000. The four streaks are due to different exposures that were recorded one after another with slight pauses in between. These were combined to create this final image. The colours appear this way because each exposure used a filter to collect only very specific wavelengths of light, in this case around red and blue. Having these separate exposures is important to study and compare stars by their colours — but it also makes asteroid interlopers very obvious!

Source: ESA/Hubble/potw

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Spiral Galaxy NGC 5211

NGC 5211
Low Res. (123 KB) / Mid. Res. (999 KB) / High Res. (7.86 MB)

NGC 5211 is a face-on galaxy located in the direction of Virgo. Unlike typical spiral galaxies that have spiral arms connected directly to their central regions, this galaxy displays a gap between its central core and the arms, resulting in a ring-like structure known as a pseudoring. Additionally, a second ring-like spiral arm is also present in the central region, giving the unique appearance of a double-ring structure. The inner ring appears red, while the outer ring has a blue tint, creating a striking and contrasting visual impression. Credit: NAOJ; Image provided by Masayuki Tanaka

Distance from Earth: 180 million light-years
Instrument: Hyper Suprime-Cam (HSC)

Source: Subaru Telescope/Press Release

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Motion of Planet-Forming Spirals Captured on Video

ALMA observations of the spiral patterns in the disk around the young star
IM Lup. Credit: ALMA(ESO/NAOJ/NRAO), Tomohiro Yoshida et al.
Download image (3.6MB)

The Atacama Large Millimeter/submillimeter Array (ALMA) has captured the motion of spirals of dust around a young star and shown that the winding motion of the spiral pattern is conducive to planet formation. This provides new evidence for planet formation around this young star. The results could have implications for other young stars as well.

Observations have revealed a spiral pattern in the disk of gas and dust around the young star IM Lup located 515 light-years away in the direction of the constellation Lupus. Spiral patterns are thought to be one of the signs that a new planet will form soon, but other things, such as an already formed planet, can also form spirals. These different types of spirals cannot be distinguished by visual inspection, but they are expected to move differently over time.

To determine the origin of the spirals around IM Lup, an international research team led by Tomohiro Yoshida, a graduate student at The Graduate University for Advanced Studies, SOKENDAI and the National Astronomical Observatory of Japan (NAOJ), created a stop-motion animation of the spiral pattern using four observations taken by ALMA over the course of seven years. The motion of the spirals in the stop-motion animation shows that they were not caused by an already formed planet, and instead the spirals might be helping to form a new planet.

Tomohiro Yoshida says, “When I saw the outcome of the analysis —the dynamic visualization of the spiral in motion— I screamed with excitement. This achievement was made possible by the long-term, stable operations of the ALMA telescope, which demonstrates the world’s highest performance. In the future, we plan to conduct similar observations on other protoplanetary disks to create a documentary of the entire planetary system formation process.”

Video of artist’s impression of planet formation around a young star, showing spiral patterns which help the young planets to form. (Credit: ALMA(ESO/NAOJ/NRAO), Tomohiro Yoshida et al.)

Source: National Astronomical Observatory of Japan (NAOJ)/Science

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Detailed Article(s)

Winding Motion of Planet-Forming Spirals Captured on Video for the First Time

ALMA

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Release Information

Researcher(s) Involved in this Release

• Tomohiro Yoshida (NAOJ/SOKENDAI)
• Hideko Nomura (NAOJ/SOKENDAI)
• Kiyoaki Doi (Max Planck Institute for Astronomy)
• Marcelo Barraza-Alfaro (Massachusetts Institute of Technology)
• Richard Teague (Massachusetts Institute of Technology)
• Kenji Furuya (RIKEN)
• Yoshihide Yamato (RIKEN)
• Takashi Tsukagoshi (Ashikaga University)

Coordinated Release Organization(s)

• National Astronomical Observatory of Japan
• Massachusetts Institute of Technology
• RIKEN
• The Graduate University for Advanced Studies, SOKENDAI
• Ashikaga University

Paper(s)

• Tomohiro C. Yoshida et al. “Winding Motion of Spirals in a Gravitationally Unstable Protoplanetary Disk”, in Nature Astronomy, DOI: 10.1038/s41550-025-02639-y

Related Link(s)

• Motion of Planet-Forming Spirals Captured on Video (SOKENDAI)

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Dwarf galaxies linked by massive intergalactic gas bridge

An image of the diffuse hydrogen emission seen by ASKAP overlaid with an optical image of the region.
Credit: ICRAR, N. Deg, Legacy Surveys (D.Lang / Perimeter Institute).

CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country.
Credit: Alex Cherney/CSIRO

Left: Radio image of neutral hydrogen in and around NGC 4532 / DDO 137 using ASKAP. Right: an optical image of the galaxy from the Legacy Surveys. Credit: ICRAR and D.Lang (Perimeter Institute).

Astronomers find 'bridge' of gas between galaxies

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Astronomers have made a groundbreaking discovery of a colossal bridge of neutral hydrogen gas linking two dwarf galaxies.

Researchers from The University of Western Australia node at the International Centre for Radio Astronomy Research (ICRAR) have uncovered an immense structure, which spans an astonishing 185,000 light-years between galaxies NGC 4532 and DDO 137, located 53 million light-years from Earth.

The study, published overnight in the Monthly Notices of the Royal Astronomical Society, also revealed that a vast tail of gas accompanied the bridge, extending 1.6 million light-years, making it the longest-ever observed.

Lead author, ICRAR UWA astronomer Professor Lister Staveley-Smith, said the discovery marked a significant step forward in understanding how galaxies interact.

“Our modelling showed that the tidal forces acting between these galaxies, alongside their proximity to the massive Virgo cluster of galaxies, played a crucial role in the gas dynamics we observed,” Professor Staveley-Smith said.

“As the galaxies rotated around each other and moved toward the hot gas cloud surrounding the Virgo cluster, which was 200 times hotter than the Sun’s surface, they experienced what is known as ram pressure, which stripped and heated the gas from the galaxies.

“The process is akin to atmospheric burn-up when a satellite re-enters the Earth’s upper atmosphere, but has extended over a period of a billion years.

“The density of electrons and the speed at which galaxies are falling into the hot gas cloud are enough to explain why so much gas has been pulled away from the galaxies and into the bridge and surrounding areas.”

The observations were part of the Widefield ASKAP L-band Legacy All-sky Survey (WALLABY). This large-scale project maps the sky and studies the distribution of hydrogen gas in galaxies, using the ASKAP radio telescope, owned and operated by CSIRO, Australia’s national science agency.

Co-author and ICRAR UWA astrophysicist Professor Kenji Bekki said researchers discovered the colossal gas formations by using high-resolution observations of neutral hydrogen.

“Neutral hydrogen plays a crucial role in the formation of stars, making this finding fundamental to understanding how galaxies interact and evolve, particularly in dense environments,” Professor Bekki said.

Professor Staveley-Smith said the system had strong similarities with our own Milky Way and Magellanic System, providing a unique opportunity to study such interactions in detail.

“Understanding these gas bridges and their dynamics provides critical insights into how galaxies evolve over time, how galactic gas is redistributed, and the varying conditions under which galaxies may or may not form stars,” he said.

“This contributes to our broader understanding of the most massive structures in the Universe and their life cycles, which helps us grasp more about their vast complexities and history of star formation.”

Source: International Center for Radio Astronomy Research (ICRAR)/News

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Publication:

WALLABY Pilot Survey: the extensive interaction of NGC 4532 and DDO 137 with the Virgo cluster

Multimedia: Download

Media Support:

For interview requests, please contact:

Charlene D’Monte
ICRAR Media Contact | charlene.dmonte@icrar.org | +61 468 579 311| +61 8 6488 7758

Interviews

Professor Lister Staveley-Smith | ICRAR/UWA

Professor Kenji Bekki | ICRAR/UWA

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

This artist’s illustration shows a rapidly feeding black hole that is emitting powerful gas outflows.
Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani

Using cutting-edge technology on the Very Large Telescope in Chile, the GRAVITY+ team managed to peer deep into the most luminous quasar known: a galaxy more than 12 billion light-years away. The astronomers were able to resolve its inner structure and more accurately determine the mass of its central black hole, which is much less than expected with the usual relations. In addition, they also found a prominent outflow, rather than most of gas rotating around the black hole. This shows that astronomers can now use GRAVITY+ to study active galaxies in the same epochs as JWST.

This pioneering observation, the first of its kind at such a high redshift, was made possible by the new Adaptive Optics (AO) systems recently installed at the Very Large Telescope Interferometer (VLTI). Developed by the Max Planck Institute for Extraterrestrial Physics (MPE) and the GRAVITY+ consortium, the AO upgrade significantly improves the correction of atmospheric blurring – adapting technology previously implemented in the ERIS instrument – to allow for deeper, more sensitive observations of the distant Universe.

The target of the observation is the most luminous known quasar (QSO) at redshift 4 – more than 12 billion light-years away and well before the era known as “cosmic noon.” The quasar studied here is an extreme object whose discovery was only reported by a team of Australian astronomers in 2024. Using the GRAVITY+ instrument, the team now resolved its “broad line region” (BLR) – the area of gas swirling around the supermassive black hole at the galaxy’s center – giving them a direct view into how material is moving under the black hole’s gravitational pull. Combining these data with a spectrum from the ERIS instrument, the team simultaneously analyzed the H-beta and H-gamma emission lines, yielding a robust and detailed kinematic model of the gas dynamics in this region.

The best-fit model of the broad-line region overlaid with a schematic explaining the geometry. We see the BLR of the galaxy edge-on. The blue part is the prominent outflow directed towards us; the red part is the reverse outflow, which is almost completely hidden from sight. Credit: MPE, GRAVITY+

A Powerful Outflow

In a second surprising result, the team found that 80% of the gas in the BLR is not rotating around the central black hole, but is being blown outwards at speeds of up to 10,000 km/s. “This is the most prominent outflow we’ve seen, and rather than studying the gas on larger scales after it has interacted with the gas in the host galaxy, these data have enabled us to resolve its launching site,” explains Taro Shimizu, who led the observations and participated in the analysis. These outflows are thought to play a crucial role in regulating galaxy growth and black hole accretion, so resolving them at their launching point is a major step forward in understanding galaxy evolution.

These results were achieved in collaboration with the new Max Planck Partner Group in Beijing led by Jinyi Shangguan, and they demonstrate that infrared interferometry can now reach into the same epoch as JWST, offering complementary insights with far higher spatial resolution.

Source: Max Planck Institute for Extraterrestrial Physics (MPE)/Press Releases

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Contact:

Richard Davies
scientis
Tel: +49 89 30000-3298
Fax: +49 89 30000-3390

davies@mpe.mpg.de

Taro Shimizu
scientist
Tel: +49 89 30000-3392
Fax: +49 89 30000-3569
shimizu@mpe.mpg.de

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Original publication

GRAVITY+ Collaboration
Spatially resolved broad line region in a quasar at z=4 – Dynamical black hole mass and prominent outflow
Submitted to A&A

Source

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More 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. more

Sharper infrared eyes for the VLT: ERIS sees first light

November 23, 2022

The Enhanced Resolution Imager and Spectrograph (ERIS), a science instrument which was built by a consortium under the leadership of the Max Planck Institute for Extraterrestrial Physics, has successfully completed its first test observations. One of them exposed the heart of the galaxy NGC 1097 in mesmerising detail.  more

 

 

 

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NASA’s Webb Explores Largest Star-Forming Cloud in Milky Way

Image A: Sagittarius B2 (NIRCam Image)

Stars, gas and cosmic dust in the Sagittarius B2 molecular cloud glow in near-infrared light, captured by Stars, gas and cosmic dust in the Sagittarius B2 molecular cloud glow in near-infrared light, captured by Webb’s NIRCam instrument. The darkest areas of the image are not empty space but are areas where stars are still forming inside dense clouds that block their light. Image: NASA, ESA, CSA, STScI, Adam Ginsburg (University of Florida), Nazar Budaiev (University of Florida), Taehwa Yoo (University of Florida); Image Processing: Alyssa Pagan (STScI)

Image B: Sagittarius B2 (MIRI Image)

Webb’s MIRI instrument shows the Sagittarius B2 region in mid-infrared light, with warm dust glowing brightly. Only the brightest stars emit strongly enough to appear through the dense clouds as blue pinpoints. Image: NASA, ESA, CSA, STScI, Adam Ginsburg (University of Florida), Nazar Budaiev (University of Florida), Taehwa Yoo (University of Florida); Image Processing: Alyssa Pagan (STScI)

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NASA’s James Webb Space Telescope has revealed a colorful array of massive stars and glowing cosmic dust in the Sagittarius B2 molecular cloud, the most massive and active star-forming region in our Milky Way galaxy.

“Webb’s powerful infrared instruments provide detail we’ve never been able to see before, which will help us to understand some of the still-elusive mysteries of massive star formation and why Sagittarius B2 is so much more active than the rest of the galactic center,” said astronomer Adam Ginsburg of the University of Florida, principal investigator of the program.

The difference longer wavelengths of light make, even within the infrared spectrum, are stark when comparing the images from Webb’s MIRI and NIRCam (Near-Infrared Camera) instruments. Glowing gas and dust appear dramatically in mid-infrared light, while all but the brightest stars disappear from view.

In contrast to MIRI, colorful stars steal the show in Webb’s NIRCam image, punctuated occasionally by bright clouds of gas and dust. Further research into these stars will reveal details of their masses and ages, which will help astronomers better understand the process of star formation in this dense, active galactic center region. Has it been going on for millions of years? Or has some unknown process triggered it only recently?

Astronomers hope Webb will shed light on why star formation in the galactic center is so disproportionately low. Though the region is stocked with plenty of gaseous raw material, on the whole it is not nearly as productive as Sagittarius B2. While Sagittarius B2 has only 10 percent of the galactic center’s gas, it produces 50 percent of its stars.

“Humans have been studying the stars for thousands of years, and there is still a lot to understand,” said Nazar Budaiev, a graduate student at the University of Florida and the co-principal investigator of the study. “For everything new Webb is showing us, there are also new mysteries to explore, and it’s exciting to be a part of that ongoing discovery.”

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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Related Information

Read more: NASA’s Webb Reveals New Features in Heart of Milky Way

Explore: ViewSpace interactive image tour of the center of the Milky Way

Explore: ViewSpace interactive views of the Eagle Nebula in different forms of light

Read more: Webb’s Star Formation Discoveries

Read more: Star formation in the Cat’s Paw Nebula

More Webb News

More Webb Images

Webb Science Themes

Webb Mission Page

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NuSTAR Observes a Neutron Star X-ray Binary

An artist's impression of an X-ray binary, in which a compact object like the neutron star in GX 13+1 accretes matter from a low-mass stellar companion. Image credit: NASA. Download Image

Over the past week, NuSTAR observed the X-ray binary GX 13+1 in coordination with an observation by NASA’s Imaging X-ray Polarimetry Explorer (IXPE). This is a peculiar star system in which a neutron star accretes matter from a companion having mass smaller than the Sun through a disk of plasma. X-ray emission from this system originates near the neutron star, where the accretion flow of material terminates in "boundary/spreading" layers, impacting on the surface of the neutron star. A wind of gas above the accretion disk is also sometimes observed in this system forming a cloud of high energy electrons in an extended corona above the disk. The nature and the geometry of such an extended accretion disk corona are not yet fully understood. Previous IXPE observations of GX 13+1 have provided measurements of the corona during periodic dipping periods in which the total X-ray flux is lower when the central region is obscured by the accretion stream and the X-ray emission is then dominated by the contribution from an extended corona. The simultaneous NuSTAR observation of GX 13+1 last week was crucial to obtain high-resolution observations at energies above 6 keV, outside the capabilities of IXPE. This was a missing piece from two previous IXPE observations, and will provide a more accurate probe into the accretion disk and corona geometry.

Authors: Alessandro Di Marco (Researcher, National Institute for Astrophysics, Italy)

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

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Spiral, elliptical or neither?

NGC 2775

A galaxy seen face-on, with a slightly elliptical disc that appears to have a hole in the centre like a doughnut. In the hole, the core is a brightly glowing point that shines light out beyond the edge of the disc. Around the hole is an inner ring of dust, and at the galaxy’s edge is a thicker outer ring of dust, with a swirling web of dust strands in between. Blue stars and red nebulae are visible behind the dust. Credit: ESA/Hubble & NASA, F. Belfiore, J. Lee and the PHANGS-HST Team

Today’s NASA/ESA Hubble Space Telescope Picture of the Week features a galaxy that’s hard to categorise. The galaxy in question is NGC 2775, which lies 67 million light-years away in the constellation Cancer (The Crab). NGC 2775 sports a smooth, featureless centre that is devoid of gas, resembling an elliptical galaxy. It also has a dusty ring with patchy star clusters, like a spiral galaxy. Which is it, then: spiral or elliptical — or neither?

Because we can only view NGC 2775 from one angle, it’s difficult to say for sure. Some researchers have classified NGC 2775 as a spiral galaxy because of its feathery ring of stars and dust, while others have classified it as a lenticular galaxy. Lenticular galaxies have features common to both spiral and elliptical galaxies.

It’s not yet known exactly how lenticular galaxies come to be, and they might form in a variety of ways. Lenticular galaxies might be spiral galaxies that have merged with other galaxies, or that have mostly run out of star-forming gas and lost their prominent spiral arms. They also might have started out more similar to elliptical galaxies, then collected gas into a disk around them.

Some evidence suggests that NGC 2775 has merged with other galaxies in the past. Invisible in this Hubble image, NGC 2775 has a tail of hydrogen gas that stretches almost 100 000 light-years around the galaxy. This faint tail could be the remnant of one or more galaxies that wandered too close to NGC 2775 before being stretched apart and absorbed. If NGC 2775 merged with other galaxies in the past, it could explain the galaxy’s strange appearance today.

A Hubble image of NGC 2775 was previously released in 2020. The new version adds observations of a specific wavelength of red light that is emitted by clouds of hydrogen gas surrounding massive young stars.

Source: ESA/Hubble/potw

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NASA's Chandra Finds Black Hole With Tremendous Growth

Illustration and X-ray Image of RACS J0320-35
Credit: X-ray: NASA/CXC/INAF-Brera/L. Ighina et al.; Illustration: NASA/CXC/SAO/M. Weiss;
Image Processing: NASA/CXC/SAO/N. Wolk

JPEG (127.3 kb) - Large JPEG (7.8 MB) - Tiff (17.7 MB) - More Images

A Tour of TOI 1227 b - More Videos

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This graphic describes the discovery of a distant black hole that is growing at one of the fastest rates ever seen, as described in our latest Chandra press release. The main panel is an artist’s illustration of the quasar named RACS J0320-35, which is located about 12.8 billion light-years from Earth. This means the quasar is being seen only about 920 million years after the big bang.

A quasar is a black hole with large amounts of material in its gravitational grasp, contained in a surrounding disk. These disks generate huge amounts of light, making quasars like RACS J0320-35 visible at enormous distances. The illustration shows this captured material as the red, orange and yellow swirls around the black sphere that represents the black hole. It also shows a jet of energetic particles blasting away from the black hole to the lower right.

After discovering this quasar with other telescopes in 2023, a team of researchers then used Chandra to examine how fast RACS J0320-35 is pulling matter onto the black hole’s surface and, as a result, growing. The Chandra data are shown in the inset in purple.

When matter is pulled toward a black hole it is heated and produces intense radiation over a broad spectrum, including X-rays and optical light. This radiation creates pressure on the infalling material. When the rate of infalling matter reaches a critical value, the radiation pressure balances the black hole's gravity and matter cannot normally fall inwards any more rapidly. That maximum is referred to as the Eddington rate.

Scientists think that black holes growing more slowly than the Eddington rate need to be born with masses of about 10,000 Suns or more so they can reach a billion solar masses within a billion years after the big bang — as has been observed in RACS J0320-35. A black hole with such a high birth mass could directly result from an exotic process: the collapse of a huge cloud of dense gas containing unusually low amounts of elements heavier than helium, conditions that may be extremely rare.

If RACS J0320-35 is indeed growing at a high rate — estimated at 2.4 times the Eddington limit — and has done so for a sustained amount of time, its black hole could have started out in a more conventional way, with a mass less than a hundred Suns, caused by the implosion of a massive star.

To figure out how fast this black hole is growing (between 300 and 3,000 Suns per year), the researchers compared computer models with the X-ray signature, or spectrum, from Chandra, which gives the amounts of X-rays at different energies. They found the Chandra spectrum closely matched what they expected from models of a black hole growing faster than the Eddington rate. Data from optical and infrared light also supports the interpretation that this black hole is packing on weight faster than the Eddington limit allows.

Another scientific mystery addressed by this result concerns the cause of jets of particles that move away from some black holes at close to the speed of light that the team detected in RACS J0320-35. Jets like this are rare for quasars, which may mean that the rapid rate of growth of the black hole is somehow contributing to the creation of these jets.

A paper describing these results has been accepted for publication i. n The Astrophysical Journal Letters and is available he,brre. The first author of the study is Luca Ighina of the Center for . Astrophysics | Harvard & Smithsonian (CfA) in Cambridge, Mass. A ,hr full list of authors can be found in the paper.

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's Chandra Finds Black Hole With Tremendous Growth

Source: NASA’s Chandra X-ray Observatory

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Visual Description:

This release features a quasar located 12.8 billion light-years from Earth, presented as an artist’s illustration and an X-ray image from NASA’s Chandra X-ray Observatory.

In the artist's illustration, the quasar, RACS J0320-35, sits at our upper left, filling the left side of the image. It resembles a spiraling, motion-blurred disk of orange, red, and yellow streaks. At the center of the disk, surrounded by a glowing, sparking, brilliant yellow light, is a black egg shape. This is a black hole, one of the fastest-growing black holes ever detected. The black hole is also shown in a small Chandra X-ray image inset at our upper right. In that depiction, the black hole appears as a white dot with an outer ring of neon purple.

The artist's illustration also highlights a jet of particles blasting away from the black hole at the center of the quasar. The streaked silver beam starts at the core of the distant quasar, near our upper left, and shoots down toward our lower right. The blurry beam of energetic particles appears to widen as it draws closer and exits the image.

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Fast Facts for RACS J0320-35:

Scale: Image is about 21 arcsec (390,000 light-years) across.
Category: Quasars & Active Galaxies, Black Holes
Coordinates (J2000): RA 03h 20m 21.4s | Dec -35° 21´ 04.13"
Constellation: Fornax
Observation Dates: 3 observations from Jul 2023-Dec 2023
Observation Time: 16 hours 45 minutes
Obs. ID: 26709, 27112, 29162
Instrument: ACIS
References: Ighina, L. et al., 2025, ApJ, Accepted;
Color Code: X-ray: purple
Distance Estimate: About 12.8 billion light-years from Earth (z=6.13)

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Are Quasars Growing in Secret?

An artist’s illustration of a distant lumin.ous quasar
Credit: NASA, ESA and J. Olmsted (STScI)

Title: Quasar Lifetime Measurements from Extended Lyα Nebulae at z∼6
Authors: Dominika Ďurovčíková et al.
First Author’s Institution: MIT Kavli Institute for Astrophysics and Space Research
Status: Published in ApJ

Observations have shown that galaxies, from our own Milky Way to far out into the distant universe, often host supermassive black holes at their centres. While the exact growth history of supermassive black holes is still uncertain, astronomers think that they likely begin as much less massive black holes, which grow primarily by eating up gas in a process known as accretion. As gas falls into the black hole, it releases a huge amount of energy, allowing astronomers to observe accreting black holes even when they’re billions of light-years away from us. The most luminous accreting supermassive black holes are known as quasars.

A supermassive black hole pulls gas in towards itself due to the force of gravity, but light emitted by the gas simultaneously exerts an outward pressure known as radiation pressure. The faster gas is being pulled into the black hole, the more light is emitted by the gas, and the stronger the pressure becomes. Eventually, the pressure will win out over gravity, preventing the black hole from accreting more gas. The theoretical maximum rate at which a black hole could accrete gas, without the gas being blown out by radiation pressure, is known as the Eddington rate.

If you took a black hole that initially weighed about 100 times the mass of our Sun and consistently fed it at the Eddington rate, it would take about 1 billion years to grow to the size of a supermassive black hole. However, measurements of quasar lifetimes suggest that black holes don’t continuously accrete at the Eddington rate, and instead, black holes go through phases of accretion. As a result, we should not expect to find supermassive black holes within the first billion years of the universe’s history.

But the universe loves to throw astronomers curveballs. Indeed, we have observed quasars less than 1 billion years after the Big Bang, suggesting that this simple picture of supermassive black hole growth is not quite right. Many mechanisms have been proposed as ways to speed up black hole growth, including accretion rates higher than the Eddington rate, mergers between two black holes, and phases of obscured growth during which the black hole accretes at the Eddington rate, but most of the light released in this process is hidden from view.

Today’s authors tackle the question of whether black holes have substantial phases of obscured growth by measuring the lifetimes of early universe quasars. Previous measurements have suggested that these quasars have only been active for less than 1 million years. However, the method that was previously used could be underestimating quasar lifetimes if there was a period of obscured growth. To determine whether this is the case, today’s authors use a different, independent method of measuring the quasar’s lifetime; if there’s a significant mismatch between the two age estimates, then it’s likely that the quasar has had significant periods of obscured growth.

The key to the methods used by today’s authors is that they probe different lines of sight to the quasar. Previous methods quantified the effect of a quasar’s light on the intergalactic medium (the diffuse gas in between galaxies) along the line of sight from the quasar to us. The method used in today’s article measures the size of a nebula of ionised gas, in the plane of the sky, at a right angle to the line of sight. While light from the quasar may have been obscured along our line of sight, it’s unlikely to have also been obscured at a different angle at the exact same time.

A quasar emits a lot of photons capable of ionising hydrogen, and as a result, a quasar can carve out bubbles of ionised gas in the otherwise neutral circumgalactic medium. The size of the ionised gas bubble, or nebula, grows at the speed of light, so if you know the size of the nebula, you can estimate the time since quasar activity began. Today’s authors looked for ionised gas in the circumgalactic medium of six early universe quasars, all of which are estimated to have very short lifetimes based on line-of-sight measurements.

To observe ionised nebulae in the circumgalactic medium, today’s authors use observations from the Very Large Telescope’s Multi-Unit Spectroscopic Explorer (MUSE). The first three panels of Figure 1 show you (left to right) the quasar; the point-spread function (PSF), or a model of how the quasar’s light diffracts as it’s observed by MUSE; and the image of the region surrounding the quasar once you subtract the PSF from the image. Each pixel is colour-coded by brightness. The last two panels also show the PSF-subtracted image, but are instead colour-coded by the ratio of signal to noise in each pixel. In the last panel, the signal has been smoothed out, and you can see the structure of a nebula (outlined in red) emerge from the image.

Figure 1: To observe the nebula (red outlined region in the rightmost panel), you have to subtract out the light coming from the quasar (leftmost panel). Adapted from Ďurovčíková et al. 2025

Figure 2: The age estimates derived by today’s authors (y-axis) are similar to the line-of-sight age estimates (x-axis), and generally follow a one-to-one relationship, suggesting that line-of-sight obscuration effects are not leading astronomers to underestimate the age of a quasar. Adapted from Ďurovčíková et al. 2025

Only three of the six quasars have a detected nebula. In the case of the non-detections, the authors argue that this is likely because the nebulae are just too small to be resolved by the telescope, rather than the nebulae being too faint. In fact, the nebulae could have been ten times fainter than the ones observed, and they still would have been detected. As a result, the authors can only estimate the ages of three of the quasars and place upper limits on the ages of the other three.

Figure 2 shows the agreement between the ages implied by nebula sizes (y-axis) and the pre-existing line-of-sight age estimates (x-axis). The grey shaded region indicates that ages below about 7,600 years could not have been detected. The black dotted line shows the one-to-one agreement between the two age estimates, and individual measurements are shown by the red squares with error bars.

Age estimates from the two methods are broadly pretty consistent, suggesting that obscuration effects are not causing one method to be severely underestimating the lifetime of a quasar. Therefore, for these six quasars, it seems unlikely that their growth can be primarily explained by phases of obscured growth. Instead, some other mechanism must have allowed these black holes to grow rapidly during the early universe and reach their supermassive sizes.

The mystery of how supermassive black holes can grow so quickly is still to be solved, but today’s article shows us that we haven’t been missing phases of obscured growth. The results of today’s article provide an independent measurement of quasar lifetimes, which models of supermassive black hole growth should be able to explain.

Original astrobite edited by Cesily King.

Source: American Astronomical Societ/AAS-Nova

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About the author, Nathalie Korhonen Cuestas:

Nathalie Korhonen Cuestas is a second-year PhD student at Northwestern University, where her research focuses on the chemical evolution of galaxies.

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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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NASA’s Hubble Sees White Dwarf Eating Piece of Pluto-Like Object

This artist’s concept shows a white dwarf surrounded by a large debris disk. Debris from pieces of a captured, Pluto-like object is falling onto the white dwarf. Credits: Artwork: NASA, Tim Pyle (NASA/JPL-Caltech)

In our nearby stellar neighborhood, a burned-out star is snacking on a fragment of a Pluto-like object. With its unique ultraviolet capability, only NASA’s Hubble Space Telescope could identify that this meal is taking place.

The stellar remnant is a white dwarf about half the mass of our Sun, but that is densely packed into a body about the size of Earth. Scientists think the dwarf’s immense gravity pulled in and tore apart an icy Pluto analog from the system’s own version of the Kuiper Belt, an icy ring of debris that encircles our solar system. The findings were reported on September 18 in the Monthly Notices of the Royal Astronomical Society.

The researchers were able to determine this carnage by analyzing the chemical composition of the doomed object as its pieces fell onto the white dwarf. In particular, they detected “volatiles” — substances with low boiling points — including carbon, sulphur, nitrogen, and a high oxygen content that suggests the strong presence of water.

“We were surprised,” said Snehalata Sahu of the University of Warwick in the United Kingdom. Sahu led the data analysis of a Hubble survey of white dwarfs. “We did not expect to find water or other icy content. This is because the comets and Kuiper Belt-like objects are thrown out of their planetary systems early, as their stars evolve into white dwarfs. But here, we are detecting this very volatile-rich material. This is surprising for astronomers studying white dwarfs as well as exoplanets, planets outside our solar system."

Only with Hubble

Using Hubble’s Cosmic Origins Spectrograph, the team found that the fragments were composed of 64 percent water ice. The fact that they detected so much ice meant that the pieces were part of a very massive object that formed far out in the star system’s icy Kuiper Belt analog. Using Hubble data, scientists calculated that the object was bigger than typical comets and may be a fragment of an exo-Pluto.

v They also detected a large fraction of nitrogen – the highest ever detected in white dwarf debris systems. “We know that Pluto's surface is covered with nitrogen ices,” said Sahu. “We think that the white dwarf accreted fragments of the crust and mantle of a dwarf planet.”

Accretion of these volatile-rich objects by white dwarfs is very difficult to detect in visible light. These volatile elements can only be detected with Hubble’s unique ultraviolet light sensitivity. In optical light, the white dwarf would appear ordinary.

About 260 light-years away, the white dwarf is a relatively close cosmic neighbor. In the past, when it was a Sun-like star, it would have been expected to host planets and an analog to our Kuiper Belt.

Like seeing our Sun in future

Billions of years from now, when our Sun burns out and collapses to a white dwarf, Kuiper Belt objects will be pulled in by the stellar remnant’s immense gravity. “These planetesimals will then be disrupted and accreted,” said Sahu. “If an alien observer looks into our solar system in the far future, they might see the same kind of remains we see today around this white dwarf.”

The team hopes to use NASA’s James Webb Space Telescope to detect molecular features of volatiles such as water vapor and carbonates by observing this white dwarf in infrared light. By further studying white dwarfs, scientists can better understand the frequency and composition of these volatile-rich accretion events.

Sahu is also following the recent discovery of the interstellar comet 3I/ATLAS. She is eager to learn its chemical composition, especially its fraction of water. “These types of studies will help us learn more about planet formation. They can also help us understand how water is delivered to rocky planets,” said Sahu.

Boris Gänsicke, of the University of Warwick and a visitor at Spain’s Instituto de Astrofisica de Canarias, was the principal investigator of the Hubble program that led to this discovery. “We observed over 500 white dwarfs with Hubble. We’ve already learned so much about the building blocks and fragments of planets, but I’ve been absolutely thrilled that we now identified a system that resembles the objects in the frigid outer edges of our solar system,” said Gänsicke. “Measuring the composition of an exo-Pluto is an important contribution toward our understanding of the formation and evolution of these bodies.”

The Hubble Space Telescope has been operating for more than three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

White Dwarf Eating Pluto-Like Object

Source: NASA's/missions/Hubble News

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Ten years of gravitational-wave astronomy and the clearest signal yet

Artist’s impression of a newly-formed black hole ringing down after a binary black hole merger while emitting gravitational waves. Credit: Maggie Chiang for the Simons Foundation

To the point:

• Gravitational waves: On 14 September 2015, the first detection of gravitational waves from a binary black hole coalescence, GW150914, marked a major milestone in astronomy and the beginning of a new era of cosmic observation.


• Technological and theoretical advances: The outstanding improvements of the detectors, waveform models and analysis methods have enabled unprecedented observations in the last decade: about 300 coalescences of black holes and neutron stars have been detected.


• New discovery: A binary black hole coalescence announced today (GW250114) is the clearest signal to date. It allowed scientists to conduct some of the most stringent tests of general relativity, identify or constrain at least three gravitational-wave tones emitted during the ringdown, which occurs shortly after the merger, and confirm Hawking’s black hole area theorem.


• Multi-messenger astronomy: The first gravitational-wave detection of a neutron star coalescence in 2017 (GW170817) demonstrated the ability to observe cosmic events through both gravitational and electromagnetic waves.


• Ongoing innovative research: AEI researchers continue to develop ever more accurate waveform models, fast and efficient analysis methods, and advanced detector technologies in preparation for upcoming LIGO-Virgo-KAGRA observing runs and next-generation detectors that promise deeper insights into cosmic events.

Visualization of a numerical-relativity simulation of the first binary black-hole merger observed by the LIGO detectors on 14 September 2015. Credit: S. Ossokine, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes project, D. Steinhauser (Airborne Hydro Mapping GmbH)

The first detection of gravitational waves from a binary black hole merger

On 14 September 2015, a signal arrived on Earth, carrying information about a pair of black holes that had spiraled together and merged in a distant galaxy. The twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the first-ever detection of gravitational waves from merging black holes. Since then, about 300 other coalescences of black holes and neutron stars have been observed, ushering in a new era of astronomy. Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI) and Leibniz University Hannover have made crucial contributions in many key areas and continue to shape its future.

“It has been an incredible journey that has brought us to this remarkable milestone 10 years ago. From the field’s early days, our researchers have been driving the development of new technologies and analysis techniques,” says Karsten Danzmann, director at the AEI and director of the Institute for Gravitational Physics at Leibniz University Hannover. “Today, we continue to build on this momentum as we work towards a future where gravitational-wave astronomy will reveal even more secrets of the Universe.”

The historic discovery enabled astronomers to observe the Universe through three different means. They had previously captured electromagnetic waves, such as visible light, X-rays, and radio waves, as well as high-energy particles and neutrinos. However, on 14 September 2015 researchers observed a cosmic event for the first time by detecting the ripples it caused in spacetime. For the discovery, Rai Weiss, Kip Thorne, and Barry Barish were awarded the Nobel Prize in Physics in 2017.

Today, the LIGO-Virgo-KAGRA (LVK) collaboration operates an international gravitational-wave detector network consisting of the two LIGO instruments in the USA, the Virgo detector in Italy, KAGRA in Japan, and GEO600 in Germany. Together they have captured a total of about 300 black hole coalescences, some of which are confirmed while others await further analysis.

Ringing Black Hole Animation (GW250114)

Credit: H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), K. Mitman (Cornell University). More

Exciting results from the clearest signal yet

The improved detector sensitivity, state-of-the-art waveform modeling, and highly efficient data analysis are exemplified in the recent discovery of a gravitational-wave signal, GW250114, produced by the coalescence of two black holes. The event was similar to the first detection, as both came from a coalescence of black holes with masses between 30 to 40 times that of our Sun about 1.3 billion light-years away. But thanks to a decade of technological, theoretical, and modeling advances the GW250114 signal is dramatically clearer and its properties can be inferred accurately.

In essence, the recent detection of GW250114 allowed the LVK team to “hear” two black holes growing as they merged into one, thereby verifying Hawking’s theorem. Furthermore, in the published study, the researchers were able, for the first time, to confidently pick out two distinct gravitational-wave modes or tones in the ringdown. This is the phase when the black hole settles into its final state right after the merger. The modes are like characteristic sounds a bell would make when struck; they have somewhat similar frequencies but die out at different rates, which makes them hard to identify. The improved data for GW250114 meant that the team could extract the two tones, demonstrating that the black hole’s ringdown occurred exactly as predicted by the rotating black hole solution in general relativity.

Visualization of a binary black hole merger consistent with the gravitational-wave event called GW250114. The gravitational waves are shown separated into the two modes of the ringing remnant black hole that were identified in the GW250114 observation: the quadrupolar fundamental mode (labeled “First tone”) and its first overtone (“Second tone”). It also shows a predicted third tone that the data place limits on. Credit: H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), K. Mitman (Cornell University)

Brand-new study presents most stringent tests of general relativity and black hole nature

Today, the LVK submitted another study to Physical Review Letters that places limits on a predicted third tone in the GW250114 signal, and performs some of the most stringent tests yet of general relativity’s accuracy in describing merging black holes. Based on this signal alone, some of those tests are two to three times more stringent than the same tests obtained by combining dozens loudest events from the most recent gravitational-wave signal catalog (GWTC-4.0).

“Not only were we able to conduct some of the most stringent verifications of general relativity. For the first time, we also constrained a third, higher-pitch tone in the ringdown of the GW250114 remnant black hole,” explains Alessandra Buonanno, director at the Max Planck Institute for Gravitational Physics and chair of the editorial team of the LVK study submitted today.

Lorenzo Pompili, a PhD student at the AEI in Potsdam and a member of the editorial team of the second LVK study, says: “We have performed black hole spectroscopy, which means studying the distinct tones emitted during the final ringdown stage of the coalescence. By constraining multiple tones and confirming that they match the expected frequencies and decay times, we can robustly test whether the remnant truly behaves like a rotating black hole.”

Buonanno adds: “Overall, Einstein’s theory of general relativity and the Kerr’s black hole solution have once again been empirically vindicated.” The rotating black hole solution discovered in 1963 by Roy Kerr has had a profound impact in astrophysics, since the discovery of quasars, and in fundamental physics.

Dance of the heavyweights: two neutron stars orbit each other, spiralling ever closer together, radiating gravitational waves in the process. This image of the real event GW170817 comes from a numerical-relativistic simulation. Credit: T. Dietrich, S. Ossokine, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), BAM collaboration

Pushing the Limits

Over the past decade, AEI researchers have contributed to the understanding of gravitational-wave events involving neutron stars. Like black holes, neutron stars are formed by supernova explosions, which mark the end of a massive star’s existence. They weigh less than black holes and, unlike black holes, emit electromagnetic waves. In August 2017, LIGO and Virgo observed a merger between two neutron stars, followed by a plethora of electromagnetic signals from gamma- to X-rays to infrared and radio waves. The kilonova sent gold and other heavy elements into space and attracted the attention of telescopes worldwide.

This multi-messenger astronomy event marked the first time that both light and gravitational waves had been captured from the same cosmic event. Today, the LVK collaboration continues to alert the astronomical community to potential neutron star mergers, who then use telescopes to search the skies for signs of kilonovae. AEI researchers routinely contribute to these alerts.

A multitude of discoveries

Other notable LVK scientific discoveries include the first detection of collisions between one neutron star and one black hole; asymmetrical mergers, in which one black hole is significantly more massive than its partner black hole; the discovery of the lightest black holes known, challenging the idea that there is a “mass gap” between neutron stars and black holes; and the most massive black hole coalescence seen yet with a merged mass of 225 solar masses. For reference, the previous record-holder for the most massive coalescence had a combined mass of 140 solar masses.

AEI researchers develop and improve sophisticated waveform models

Researchers at the AEI have developed new waveform models that are used routinely by the LVK collaboration to distinguish real cosmic sources from random fluctuations and terrestrial disturbances that appear in the detector.

Over the past decade, the institute’s scientists have continuously improved the accuracy and efficiency of their waveform models. They have developed ever more accurate waveform models that account for the complex dynamics of highly spinning black holes, such as those observed in the recent detection of GW231123. These models are essential for extracting accurate information from the signal and understanding the properties of the astrophysical objects involved in the coalescence.

The institute’s researchers have also developed new parameter estimation methods based on machine learning methods and neural networks. These provide a rapid and accurate way to infer the properties of binary black hole and binary neutron star mergers. The novel methods are particularly useful for analyzing large datasets and identifying potential signals in real-time.

Development of high-power laser systems

Researchers at the AEI and at Leibniz University Hannover have made key contributions to the high-power laser systems used in gravitational-wave detectors. These high-power laser systems are essential for the operation of the instruments, as they provide the intense and extremely pure and stable laser light needed to measure the minuscule distance changes caused by gravitational waves. The institute’s researchers have developed the main laser source currently in use in the LIGO instruments and have tested and helped implement upgrades to it. The amplifier stage of the current laser sources in the Virgo and KAGRA instruments is also based on developments and tests carried out by a collaboration between the institutes and the Laser Zentrum Hannover.

The German-British GEO600 detector south of Hannover, Germany, is a key technology development center of the international gravitational-wave research community. Technologies developed and tested in the GEO project are now used in all large gravitational-wave detectors in the world. Credit: Max Planck Institute for Gravitational Physics (Albert Einstein Institute)/Milde Marketing

Technology testbed GEO600 and squeezed light for more sensitive detectors

The German-British GEO600 gravitational-wave detector, operated by the AEI and Leibniz University Hannover, played a crucial role in the development of gravitational-wave astronomy over the past decade. As a testbed for advanced detector techniques, GEO600 enabled the development of key technologies that have improved the sensitivity of the other detectors. GEO600 was the first detector to use squeezed light in 2010. Squeezed light is a technique that reduces the quantum noise in gravitational-wave detectors, allowing them to detect weaker signals. The institutes’ researchers have developed and built squeezed-light sources for the GEO600 and Virgo detectors, and have helped to push the boundaries of squeezed-light technology. These technological advancements have increased the sensitivity of gravitational-wave detectors and have improved our ability to detect and analyze gravitational-wave signals.

Continuing the quest for new discoveries

In the coming years, the scientists and engineers of the LVK collaboration plan to further fine tune their machines, expanding their reach deeper and deeper into space. Researchers at the Max Planck Institute for Gravitational Physics and Leibniz University Hannover will continue making groundbreaking contributions to the field. “With the third-generation detectors we can expect to hear the earliest black hole mergers in the Universe, make even more precise measurements of gravitational-wave events and gain a deeper understanding of the cosmic mysteries,” explains Frank Ohme, who leads an independent research group at the AEI. Researchers at the institutes will continue to push the boundaries of detector technology, waveform model development, and analysis techniques, that drive the field forward and enable new discoveries.

The LIGO-Virgo-KAGRA Collaboration

LIGO is funded by the US National Science Foundation and operated by Caltech and MIT, which together conceived and built the project. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the United Kingdom (Science and Technology Facilities Council), and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,600 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. Additional partners are listed at my.ligo.org/census.php.

The Virgo Collaboration is currently composed of approximately 1,000 members from 175 institutions in 20 different (mainly European) countries. The European Gravitational Observatory (EGO) hosts the Virgo detector near Pisa in Italy, and is funded by Centre National de la Recherche Scientifique (CNRS) in France, the National Institute of Nuclear Physics (INFN) in Italy, the National Institute of Subatomic Physics (Nikhef) in the Netherlands, The Research Foundation – Flanders (FWO), and the Belgian Fund for Scientific Research (F.R.S.–FNRS). A list of the Virgo Collaboration groups can be found at: A list of the Virgo Collaboration groups can be found at: https://www.virgo-gw.eu/about/scientific-collaboration/. More information is available on the Virgo website at https://www.virgo-gw.eu.

KAGRA is the laser interferometer with 3-kilometer arm length in Kamioka, Gifu, Japan. The host institute is the Institute for Cosmic Ray Research (ICRR), the University of Tokyo, and the project is co-hosted by National Astronomical Observatory of Japan (NAOJ) and High Energy Accelerator Research Organization (KEK). KAGRA collaboration is composed of more than 400 members from 128 institutes in 17 countries/regions. KAGRA's information for general audiences is at the website gwcenter.icrr.u-tokyo.ac.jp/en/. Resources for researchers are accessible from gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA.

Source: Max Planck Institute for Gravitational Physics/Researche News

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Media Contacts:

Dr. Benjamin Knispel
Press Officer AEI Hannover
Tel: +49 511 762-19104
benjamin.knispel@aei.mpg.de

Dr. Elke Müller
Press Officer AEI Potsdam, Scientific Coordinator
Tel: +49 331 567-7303
elke.mueller@aei.mpg.de

Scientific contacts:

Prof. Dr. Alessandra Buonanno
Director | LSC Principal Investigator
Tel: +49 331 567-7220
Fax: +49 331 567-7298
alessandra.buonanno@aei.mpg.de
Homepage of Alessandra Buonanno

Prof. Dr. Karsten Danzmann
Director | LSC Principal Investigator
Tel: +49 511 762-2356
Fax: +49 511 762-5861
karsten.danzmann@aei.mpg.de
Homepage of Karsten Danzmann

Dr. Frank Ohme
Research Group Leader | LSC Principal Investigator
Tel: +49 511 762-17171
Fax: +49 511 762-2784
frank.ohme@aei.mpg.de
Homepage of Frank Ohme

Lorenzo Pompili
PhD Student
Tel: +49 331 567-7182
Fax: +49 331 567-7298
lorenzo.pompili@aei.mpg.de

Dr. Elisa Maggio
Marie Curie Fellow
Tel: +49 331 567-7197
elisa.maggio@aei.mpg.de

Prof. Harald Pfeiffer
Group Leader
Tel: +49 331 567-7328
Fax: +49 331 567-7298
harald.pfeiffer@aei.mpg.de

Elise Sänger
PhD Student
elise.saenger@aei.mpg.de

Dr. Jan Steinhoff
Group Leader
Tel: +49 331 567-7125
jan.steinhoff@aei.mpg.de

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Publications

1. The LIGO Scientific Collaboration; the Virgo Collaboration; the KAGRA Collaboration; Abac, A.; Abouelfettouh, I.; Acernese, F.; Ackley, K.; Adhicary, S.; Adhikari, D.; Adhikari, N. et al.: GW250114: Testing Hawking’s Area Law and the Kerr Nature of Black Holes. Physical Review Letters 135, 111403 (2025)

MPG.PuRe | | DOI | pre-print
publisher-version

2. The LIGO Scientific Collaboration; the Virgo Collaboration; the KAGRA Collaboration; Abac, A.; Abouelfettouh, I.; Acernese, F.; Ackley, K.; Adhicary, S.; Adhikari, D.; Adhikari, N.et al.: Black Hole Spectroscopy and Tests of General Relativity with GW250114. (2025)

MPG.PuRe | pre-print

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Further information

© Max Planck Institute for Gravitational Physics, Milde Marketing Science Communication

The hunters - the detection of gravitational waves

The hunters - the detection of gravitational waves. Find the video on YouTube here.

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