SPACE/COSMOS
Scientists turn radio telescopes into space scanners – sharpening view of hidden orbital threats
University of Birmingham
video:
World-first live demonstration of next-generation technology shows how repurposing scientific infrastructure can track both potentially hostile satellites and hazardous space debris.
view moreCredit: ©University of Birmingham 2026. Produced by Creative Media
Scientists have successfully demonstrated a breakthrough in how sensitive radio telescopes can be used to significantly improve the world's ability to detect, track and characterise satellites and space debris in orbit.
An international research team led by the University of Birmingham, has delivered a real-time demonstration repurposing existing scientific and commercial infrastructure as independent radar receivers to dramatically enhance the performance of current space surveillance systems.
Traditional radar systems can track objects in low earth orbit (LEO) but detecting satellites and debris at geostationary orbit (GEO), some 37,000km from Earth, requires extremely powerful transmitters.
GEO hosts many of the world's most critical space assets, including military, government and commercial communications, navigation and weather satellites. Protecting these high-value systems requires a clear and continuous picture of what is happening in space.
This means being able to spot, track and identify all objects nearby - whether they are working satellites, inactive spacecraft, or other objects - so that operators can make informed decisions and respond quickly to potential risks.
Funded by the UK Space Agency, the Long Baseline Multistatic Radar (LBMR) project incorporates radio telescopes into existing radar systems can increase sensitivity more than tenfold - enabling the detection of smaller objects at greater distances.
Professor Marco Martorella, from the University of Birmingham, said: "The successful demonstration of LBMR marks an important step towards using this technology operationally to monitor satellites and debris around our planet.
“LBMR also provides a unique platform to advance radar technologies, validate new sensing concepts, and train the next generation of RF and radar engineers. Building and retaining this expertise is key to developing the capabilities needed to detect, track, and identify space objects. This will help to protect critical space infrastructure - ensuring the safe and sustainable use of space for the future.”
The research partnership - comprising of experts from the Universities of Birmingham and Manchester, Goonhilly Earth Station, Massachusetts Institute of Technology Lincoln Laboratory, and Australia's national science agency CSIRO - demonstrated the capability live at the European Space Agency's ECSAT facility in Harwell, Oxfordshire.
During the event, representatives from government, defence and industry observed radar detections and measurements being processed in real time.
The demonstration used major UK scientific infrastructure, including the 76-metre Lovell Telescope at Jodrell Bank Observatory and the UK's e-MERLIN radio telescope network, as well as the 30m GES satellite communication antenna illustrating how research and commercial facilities can be repurposed to address emerging national security and space sustainability challenges.
Dr Chris Blount at the UK Space Agency said: “The LMBR project has been a fantastic example of innovation and collaboration by incredible UK and international talent, and an exemplar case of the capability multiplication through collaboration the International Bilateral Fund (IBF) seeks to achieve.
“The LBMR team have taken the thorny challenge of real time on-demand monitoring of space objects on geostationary orbit, and through proactive partnering and an innovative application of existing world class UK assets, have been able to demonstrate a state of the art, dual use by design, capability.
“This has been achieved without the extensive investment, time, and effort a dedicated facility would have otherwise needed, and even surpasses the capability such a facility would yield. This is exactly the innovation and engineering excellence UKSA and the IBF seeks to promote, and is a key step towards a capability to make the UK and our international partners safer and better able to respond to the challenges of a congested and contested space.”
The project has brought together partners from the UK, United States, and Australia to overcome key challenges in synchronising, distributed sensing and real-time processing.
Dr. Jason Guicheteau, Chair of NATO Sensing Technology Scientific Technical Committee said: “The successful live demonstration of the LBMR is a testament to the power of allied collaboration, showcasing the transition of foundational science into a tangible, operational capability originating out of NATO Science and Technology Organization research task groups."
Professor Gaven Smith, CB FREng – University of Manchester and former Chief Technology Officer, GCHQ said: “This is a compelling example of how research facilities and skills can be applied to the challenge of protecting important UK assets in space against a range of natural and potentially hostile threats. The need for these capabilities is becoming increasing urgent, and this application of radio telescopes shows how powerful capabilities can be developed rapidly and cost-effectively within the UK, by leveraging our research base.”
ENDS
For more information, please contact Tony Moran, International Communications Manager t.moran@bham.ac.uk or +44 (0)7827 832312
VIDEO COPYRIGHT: Please credit ©University of Birmingham 2026. Produced by Creative Media
Notes for editors
- The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 40,000 students from over 150 countries.
- England’s first civic university, the University of Birmingham is proud to be rooted in one of the most dynamic and diverse cities in the country. A member of the Russell Group and a founding member of the Universitas 21 global network of research universities, the University of Birmingham has been changing the way the world works for more than a century.
Scientists use dual-frequency images to explore black hole plasma physics
Chinese Academy of Sciences Headquarters
The first-ever image of a black hole—a glowing, ring-like structure in the heart of galaxy M87—was unveiled to the world in a landmark moment in 2019. Now, researchers have taken the next big step—by moving beyond capturing a picture of the black hole to understanding its physics through dual-frequency images.
The research was conducted by scientists at the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences (CAS), together with international collaborators, who combined horizon-scale images obtained in 2018 from the Event Horizon Telescope and the Global Millimeter Very Long Baseline Interferometry (VLBI) Array at two frequencies—1.3 mm and 3.5 mm.
By carrying out the first dual-frequency spectral study of its kind, the researchers produced a spatially resolved spectral-index map on event-horizon scales and revealed how the spectral index changes with distance from the black hole. This allowed them to determine the physical conditions of the plasma around the black hole and the processes that generate the observed radiation.
The study was published in The Astrophysical Journal Letters.
The results show that the radiation properties surrounding the black hole vary systematically with distance, as revealed by the spatial distribution of the spectral index. In the innermost region, the spectral index is positive and increases slightly with radius, suggesting that the emission remains significantly affected by synchrotron self-absorption. Farther from the black hole, the spectral index decreases and changes from positive to negative values, indicating a transition toward a more optically thin emission regime.
Remarkably, this transition occurs at a distance of about 30 μas from the black hole, consistent with the radius of the ring-like structure observed at 3.5 mm. This result suggests that the ring-like structure seen in black hole images is not merely a feature of the emission morphology, but is closely connected to the physical state of the plasma near the event horizon.
“By obtaining the first spatially resolved spectral-index distribution of the M87 black hole, we can quantitatively characterize how the radiation properties change across the region surrounding the black hole,” said Dr. ZHAO Shanshan, an assistant researcher at SHAO and the first author of the study. “This allows us to directly explore how the plasma properties vary on horizon scales and provides new clues for understanding accretion flows and jet formation.”
According to the researchers, continued advances in millimeter VLBI will enable observations at more frequencies, with higher sensitivity and time-resolved imaging capabilities. These improvements will provide much richer information about black hole accretion, jet formation, and radiation processes in strong gravitational fields, further deepening our understanding of the extreme environments surrounding black holes.
Dr. LU Rusen, a researcher at SHAO and the corresponding author of the study, noted that multi-frequency horizon-scale imaging will enable more precise studies of black hole accretion, jet formation, and strong-field gravity by disentangling the effects of plasma physics from gravitational signatures in black hole images.
This study was funded by the National Natural Science Foundation of China, China’s National Major Science and Technology Projects, CAS, and the Shanghai Municipal Government.
Journal
The Astrophysical Journal Letters
Article Title
Spatially resolved spectral properties of M87* on event horizon scales
Article Publication Date
20-Jul-2026
CHIME collaboration helps identify location of "missing" matter in the universe
Researchers from McGill, MIT and partner institutions combined fast radio bursts and incoming light from galaxies to locate a vast source of previously unaccounted-for matter
McGill University
Estimates of ordinary matter in the universe exceed the amount observed in stars and galaxies, leaving much of it unaccounted for. Researchers from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/Fast Radio Bursts Collaboration, including McGill University and MIT, have developed a new method to seek out this “missing” matter by combining galaxy locations with fast radio burst detections. A fast radio burst, or FRB, is an ultrabright, millisecond flash of radio waves emitted by extremely energetic phenomena in the distant universe.
The new method revealed not only whether missing matter was present, but also its location: specifically, in diffuse clouds surrounding galaxies and galaxy groups. The analysis also showed that the missing matter is spread over a much larger region than predicted by simulations, extending roughly four million light-years from galaxies.
“Fast radio bursts are amazingly effective in probing the distribution of matter in the universe,” said Victoria Kaspi, study co-author and Professor of Physics at McGill University. The research was led by Haochen Wang, a graduate student in MIT’s Kavli Institute for Astrophysics and Space Research, and Kiyoshi Masui, Associate Professor of Physics at MIT.
The researchers said the findings support the idea that matter is flung outside galaxies by black hole jets, exploding stars and other energetic processes, and suggest those processes are more powerful than previously thought.
“By mapping the shape of missing matter, we can understand how galaxies form and how they interact with their environment,” Wang said.
More than 2,500 signals analyzed
The team used data from two sources: the CHIME radio telescope near Penticton, B.C., and the Dark Energy Spectroscopic Instrument (DESI) in Tucson. CHIME detects incoming radio waves, including fast radio bursts, while DESI measures incoming light from over 30 million galaxies to study the puzzle of “dark energy.”
From CHIME's catalogue of detections, members of the CHIME/FRB Collaboration analyzed 2,870 FRB signals. As fast radio bursts travel through space, their signals become increasingly smeared by the matter they pass through. The researchers measured this effect and compared it with galaxy locations across the universe to determine how much of the matter was associated with galaxies and how much was diffuse matter surrounding them.
The team said these results demonstrate that fast radio bursts can be a reliable method by which to search for missing matter. As CHIME continues to detect more FRBs, they noted, this method can only improve.
“We got it to work for the first time and will get it to work even more precisely as data gets better,” Masui said.
About this study
“Measurement of the Dispersion–Galaxy Cross-Power Spectrum with the Second CHIME/FRB Catalog,” by Haochen Wang (MIT), Kiyoshi Masui (MIT), Victoria Kaspi (McGill) et al., was published in Physical Review Letters.
CHIME and CHIME/FRB are supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, and the provinces of Quebec, British Columbia and Ontario.
The study was supported in part by the U.S. National Science Foundation.
About this release
This press release was developed in collaboration with the Institute Office of Communications at MIT and based on a story by Jennifer Chu.
Journal
Physical Review Letters
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Measurement of the Dispersion–Galaxy Cross-Power Spectrum with the Second CHIME/FRB Catalog
Article Publication Date
21-Jul-2026
New technique enables LIGO to peer farther into the distant universe
Thermal imaging could boost future gravitational-wave detectors
image:
Photo shows researchers in Jonathan Richardson’s group testing a novel adaptive optics device designed to precisely reshape the surfaces of LIGO’s main mirrors.
view moreCredit: Arnaud Pele, LIGO Laboratory.
RIVERSIDE, Calif. -- Scientists at the University of California, Riverside have developed a new way to help gravitational-wave observatories see farther into the universe by solving one of their biggest challenges: tiny heat-induced distortions in the massive mirrors at the heart of the detectors.
The technique, described in a paper published in Classical and Quantum Gravity, uses thermal imaging to reveal microscopic distortions caused by powerful lasers. By measuring those distortions more precisely, observatories such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) could improve their sensitivity and detect weaker, more distant gravitational-wave events.
“The goal for the next generation of gravitational-wave detectors is to achieve about 10 times the sensitivity of today’s instruments,” said Jonathan Richardson, an associate professor of physics and astronomy at UC Riverside who led the study. “One of the key obstacles to achieving that is reducing the fundamental quantum mechanical noise that limits the precision of the measurements.”
LIGO detects gravitational waves — ripples in spacetime created by accelerating massive objects — by measuring changes in distance smaller than the width of a proton. To make those measurements, lasers circulate through the 4-kilometer-long observatory with powers approaching one megawatt.
Although LIGO’s mirrors are among the purest optical components ever made, they still absorb a tiny fraction of that laser light. The resulting heat changes the mirrors’ shape by just a few nanometers, slightly distorting the laser beam and reducing the detector’s sensitivity.
Researchers already know how to counteract those distortions by applying carefully controlled heating patterns to the mirrors. The challenge has been determining exactly how the mirrors are distorted in order to apply the optimal heating pattern.
The new method combines infrared thermal images of the mirror surface with existing wavefront measurements and computer models of heat flow to reconstruct the mirrors’ optical distortion across their entire diameter.
“You can think of it like taking an infrared picture of a car engine,” Richardson said. “An engineer can look at the temperature pattern on the outside and infer what’s happening inside the engine. We’re doing the same thing with LIGO’s mirrors.”
The idea grew out of an unexpected experimental result while Richardson’s group was testing new adaptive optics on a full-scale, 40-kilogram LIGO mirror. The experiment was designed to precisely reshape the surfaces of LIGO’s main mirrors.
“We found that if you know the surface temperature and have a good model of how heat flows through the optic, you can accurately reconstruct the optical distortions inside it,” Richardson said. “That surprising result is what led us to develop this new sensing technique.”
Unlike many LIGO upgrades, the approach relies on commercially available thermal imaging cameras mounted outside the interferometer rather than entirely new instrumentation.
“It only requires a thermal imaging camera that already meets today’s commercial standards,” Richardson said. “It doesn’t require any new technology development, which is almost unheard of for solving a LIGO instrumentation problem.”
The researchers estimate the technique could improve the strain sensitivity, the smallest fractional change in length that an instrument can detect, of the upcoming LIGO A+ upgrade by as much as 31%, allowing the observatory to detect binary neutron star mergers about 10 megaparsecs (roughly 33 million light-years) farther away on average.
“When you make the detector more sensitive, you don’t just see a little farther — you observe a much larger volume of the universe,” Richardson said. “Because the detectable volume scales with the cube of the distance, even a modest increase in sensitivity can produce a much larger increase in the number of gravitational-wave events we detect.”
The technology is also expected to become part of the baseline design for Cosmic Explorer, the proposed next-generation U.S. gravitational-wave observatory. Richardson serves as the system design lead for its mode sensing and control system.
“LIGO will serve as the pathfinder,” Richardson said. “We’ll develop and validate these techniques in the next upgrades and then use that experience to enable Cosmic Explorer.”
According to Richardson, the work fills an important gap in the technology needed for future observatories.
“Our research provides not only a way to correct these optical distortions, but now also a practical way to measure exactly how they should be corrected in the first place,” he said. “That capability will be essential for the next generation of gravitational-wave observatories and will allow us to see farther into the distant universe than ever before.”
The paper’s co-authors are Liu Tao, a former postdoctoral researcher in Richardson’s laboratory, and Pooyan Goodarzi, a doctoral student in the UCR Department of Physics and Astronomy.
The research was supported by the National Science Foundation.
The paper is titled “Error signals for overcoming the laser power limits of gravitational-wave detectors.”
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.
Journal
Classical and Quantum Gravity
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Error signals for overcoming the laser power limits of gravitational-wave detectors
SwRI, UT San Antonio-led experiment designated ready to fly by NASA
Experiment will evaluate electrolyzer designed to use local resources on Moon or Mars to support human habitation
image:
A Southwest Research Institute and University of Texas at San Antonio experiment has passed a critical NASA review, designating it ready for parabolic flight testing. The pictured flight rig contains a novel electrolyzer technology. Its performance and associated bubble dynamics will be tested in low gravity.
view moreCredit: Southwest Research Institute/UT San Antonio
SAN ANTONIO — July 21, 2026 — A Southwest Research Institute and University of Texas at San Antonio experiment has passed a critical NASA review, designating it ready for parabolic flight testing. The two institutions will evaluate the performance of a patent-pending electrolyzer, the Mars Atmospheric Reactor for Synthesis of Consumables (MARS-C), in partial gravity environments.
The project is led by SwRI’s Kevin Supak, a program manager in SwRI’s Fluids Engineering Department, and Dr. Shrihari Sankarasubramanian, an assistant professor in UT San Antonio’s Department of Biomedical and Chemical Engineering. Developed by Sankarasubramanian with NASA support, MARS-C is designed to use local resources on Mars to produce fuel, oxygen, and other life-support compounds necessary for long-term human habitation.
“The payload is ready to fly aboard an aircraft flying a parabolic profile. We have demonstrated to NASA that our design, procedures, and safety considerations have met the requirements needed to execute the parabolic flight test,” Supak said. “This will be the first demonstration of an electrolyzer that can function in Martian ambient conditions, which has one third of Earth’s gravity and significantly colder and lower atmospheric pressure.”
MARS-C is an in-situ resource utilization (ISRU) technology meant to improve production of propellants and life-support compounds on Mars, but similar technology can be applied to the Moon and other planetary bodies. It applies voltage across two electrodes to electrochemically convert simulated Martian brine and carbon dioxide into oxygen, ethanol, and other hydrocarbons.
The team adapted prototype electrochemical cells into a three-by-seven-foot payload that contains six electrochemical cells. Each cell is installed in a containment box to control the ambient humidity and simulate Martian temperatures using thermoelectric heat pumps.
“By qualifying for this parabolic flight, we get to learn how hydrocarbon-producing electrolyzers behave at Martian gravity conditions,” Sankarasubramanian said. “The resulting insights will help us improve system design and performance and put MARS-C on the pathway to potentially serve in astronaut life-support applications and chemical production on Mars.”
SwRI and UT San Antonio will test MARS-C aboard a series of parabolic flights, which will provide reduced-gravity conditions through periods of freefall created by arched flight patterns. These parabolas allow the payload to experience brief periods (about 15 to 20 seconds each) of either lunar, Martian, or zero gravity levels. This approach builds on previous work conducted by SwRI that studied boiling processes under partial gravity aboard parabolic flights. SwRI’s research showed that lower gravity affects surface bubble dynamics, which can, in turn, affect gas production rates.
“The electrolysis cells will be operated during the flight to produce ethanol and other hydrocarbons, and cameras will record the gas buildup on the electrode surfaces,” Supak said. “The equipment operating the electrochemical cells will also monitor electric currents in the cells. After the flight, we will draw fuel samples from the cells and measure their hydrocarbon content to quantify the amount of fuel produced as a function of gravity level.”
The project is supported by NASA’s TechLeap Prize, which supports future missions by advancing solutions that address NASA’s technology shortfalls, as well as the Connecting through Research Partnerships (Connect) program, which fosters collaboration between SwRI and UT San Antonio. The project is also supported by the university’s Klesse College of Engineering and Integrated Design (KCEID) and the Center for Space Technology and Operation Research (CSTOR).
This project was funded (fully or in-part) by The University of Texas at San Antonio, Office of Research and Southwest Research Institute.
For more information, visit https://www.swri.org/markets/energy-environment/fluids-engineering/fluid-mechanics-thermal-management-research/fluid-physics-space-applications.
Bubble Formation [VIDEO]
The University of Texas at San Antonio and Southwest Research Institute (SwRI) will flight test a novel electrolyzer technology to characterize its performance and associated bubble dynamics in low gravity. In this video, an electrochemical cell filled with simulated Martian brine recreates processes that produce oxygen and hydrocarbon consumables.
Credit
Southwest Research Institute/UT San Antonio
Diffuse puffs of “missing” matter surround most galaxies
An MIT-led team used bright radio bursts to illuminate a vast source of matter that was previously unaccounted for.
image:
Simulated gas distribution (blue, green, and yellow colors) around galaxies (white dots on the image). The study finds that gas in our Universe extends farther from galaxies than most simulations predict, indicating strong activity from galaxies that have expelled gas away from galaxy groups.
view moreCredit: IllustrisTNG
Takeaways:
- MIT scientists, as part of the CHIME/FRB Collaboration, are using far-off radio signals to reveal missing matter in the vast space between galaxies.
- The team has developed a new method to search out missing matter by combining locations of galaxies with detections of fast radio bursts.
- Using the new method, the researchers found that matter is flung outside a galaxy through black hole jets, exploding stars, and other highly energetic processes within a galaxy. What’s more, the findings suggest that such processes are more energetic than scientists had thought.
Cambridge, Mass. -- Stars and galaxies make up much of the universe’s ordinary, observable matter. But for decades, scientists have wrestled with a cosmic conflict: There should be much more.
Physicists have good estimates of how much matter was present in the early universe. Shortly after the Big Bang, roughly 83 percent of all matter in the universe was composed of invisible dark matter, with ordinary matter making up the rest. And yet, these estimates exceed the amount of ordinary matter seen in stars and galaxies today. Where, then, did all the missing ordinary matter go?
Now MIT scientists, as part of the CHIME/FRB Collaboration, are using far-off radio signals to reveal missing matter in the vast space between galaxies. The team has developed a new method to search out missing matter by combining locations of galaxies with detections of fast radio bursts.
A fast radio burst, or FRB, is an ultrabright, millisecond flash of radio waves emitted by extremely energetic phenomena in the distant universe. As it travels through space, the signal from a fast radio burst gets stretched, or “smeared,” in time. The more missing matter that it passes through, the more smeared the signal becomes.
The MIT-led team measured the degree of smearing experienced by thousands of FRB signals detected on Earth. Then they compared each FRB smear with locations of galaxies across the universe to determine how much of an FRB’s smearing was due to galaxy matter versus other, missing matter.
The new method revealed not only whether missing matter was present, but also where. Specifically, the researchers discovered that it exists in very diffuse clouds surrounding groups of galaxies. These clouds extend out from the galaxies, to much further distances than scientists had predicted.
“We find that, overall, where there are more galaxies, there tends to be more missing matter around them,” says Haochen Wang, a graduate student in MIT’s Kavli Institute for Astrophysics and Space Research.
The results, reported today in the journal Physical Review Letters, support the idea that matter is flung outside a galaxy through black hole jets, exploding stars, and other highly energetic processes within a galaxy. What’s more, the findings suggest that such processes are more energetic than scientists had thought.
“We’re finding missing matter that is pushed out to larger scales,” says Kiyoshi Masui, associate professor of physics at MIT. “These measurements indicate that star activity, and activity from black holes, is stronger and much more violent than predicted.”
Masui and Wang are co-authors of the new study, which includes Shion Andrew, Adam Lanman, Kenzie Nimmo, and Ryan Raikman from MIT, and collaborators from multiple other institutions as part of the CHIME/FRB Collaboration.
The shape of matter
The vast majority of ordinary, observable matter in the universe is built from baryons — a type of subatomic particle that includes protons and neutrons, and that makes up most of an atom’s mass. Scientists estimate that just 17 percent of the early universe was made from this “baryonic” matter, shortly after the Big Bang.
Some of that early matter was forged into every substantial thing we see today, from planets, stars, and galaxies, to our own bodies. But as scientists have realized, this matter doesn’t quite add up. The total mass of all the stars, galaxies, and galactic clouds is about a tenth of the baryonic matter that existed in the early universe. There must be more matter, likely in the spaces between galaxies. But the universe is vast. Any leftover matter likely exists at extremely low densities, of around a single proton per cubic meter, making it extremely challenging to detect.
Recently, however, Masui and others have found that such missing matter could be sussed out using fast radio bursts. FRBs were first discovered in 2007, and since then astronomers have detected several thousand of the mysterious, ultrashort signals from distant galaxies, billions of light years away.
“What makes FRBs good to probe missing matter is that they have a special property,” Wang says. “They start out as a very quick flash, and as they pass through matter, they smear out in time. And we can measure that smearing very precisely, which is directly proportional to how much missing matter the FRB passed through.”
Researchers have previously taken advantage of this smearing property of FRBs to detect missing matter around galaxies. These efforts have confirmed that tenous clouds exist in the vast spaces between galaxies. Masui and Wang wanted to go a step further.
“We’re not just probing if the gas is with the galaxy or not, but we are seeing the shape of the missing matter that’s around the galaxies,” Wang says. “By mapping the shape of missing matter, we can understand how galaxies form and how they interact with their environment.”
Galactic fountains
For their new study, the team mapped the shape of missing matter around galaxies by cross-correlating thousands of FRB measurements with locations of millions of galaxies. They used data from two sources: the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Dark Energy Spectroscopic Instrument (DESI) survey.
CHIME is a large radio telescope located in British Columbia, Canada, that is designed to scan the entire northern sky for incoming radio waves. The telescope is sensitive to ultrashort, ultrabright radio signals, and since it began observing, CHIME has detected about 4,000 fast radio bursts across the sky.
DESI is an instrument that is mounted on the Mayall Telescope at Kitt Peak National Observatory, near Tucson, Arizona. The instrument makes detailed measurements of the light coming from over 30 million galaxies, to provide estimates of dark energy — the mysterious force that drives the expansion of the universe.
From CHIME’s catalog of detections, members of the CHIME/FRB collaboration analyzed 2,870 FRB signals. Each signal is a burst of radio waves, at multiple wavelengths, from highest to lowest energy. The higher-energy “blue” waves typically are less affected by any missing matter they travel through, and therefore should arrive at a detector before lower-energy “red” wavelengths, which are more delayed, or “smeared,” in time.
The team measured the smearing of each FRB’s various wavelengths, which they could then directly relate to the amount of matter that the FRB must have traveled through before reaching CHIME’s detectors. Masui and Wang then correlated these measurements with the locations of over 6 million galaxies provided by DESI data. In this way, they could they could look for an association between the missing matter and the galaxies, and measure where one is in relation to the other.
Their analysis revealed a pattern: Missing baryonic matter tended to be found around galaxies and galaxy clusters. But rather than gathering close to galaxies in a dense ball, missing matter was scattered across a large radius, similar to a diffuse puff.
“A galaxy is maybe a few 100,000 light years across, and we found missing matter out to about 4 million light years,” Masui says. “That’s further than the simulations predict, by quite a bit.”
“We are finding that the activity in galaxies is messier than we thought,” Wang says. “They’re more like fountains, and really push out gas to very large distances.”
The new results show that fast radio bursts can be a reliable method by which to search for missing matter. As CHIME continues to detect more FRBs, the team says its method can only improve.
“We got it to work for the first time, and will get it to work even more precisely as data gets better,” Masui says.
CHIME and CHIME/FRB are supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada and, the provinces of British Columbia, Québec and Ontario. This study was supported in part by the U.S. National Science Foundation.
###
The spatial distribution of fast radio burst signal across the sky (above), compared against the galaxy distributions (below). The study has found a significant correlation between the two distributions, revealing missing baryonic matter in the Universe.
Credit
Haochen Wang
Written by Jennifer Chu, MIT News
Paper: “Measurement of the Dispersion–Galaxy Cross-Power Spectrum with the Second CHIME/FRB Catalog”
https://journals.aps.org/prl/abstract/10.1103/9th9-qc51
Journal
Physical Review Letters
Article Title
“Measurement of the Dispersion–Galaxy Cross-Power Spectrum with the Second CHIME/FRB Catalog”
FIU study challenges leading explanation for why galaxies stop forming stars
image:
Interacting galaxies NGC 4676, known as "The Mice," as captured by the Hubble Space Telescope. (Credit: NASA/H. Ford (JHU), G. Illingworth (UCSC/LO), M. Clampin (STScI), G. Hartig (STScI) and the ACS Science Team)
view moreCredit: Interacting galaxies NGC 4676, known as "The Mice," as captured by the Hubble Space Telescope. (Credit: NASA/H. Ford (JHU), G. Illingworth (UCSC/LO), M. Clampin (STScI), G. Hartig (STScI) and the ACS Science Team)
For decades, astronomers have cast galaxy mergers as the universe’s ultimate relationship drama: two galaxies collide, chaos erupts, black holes awaken and star formation comes to a screeching halt. Upending this long-held belief, new research from Florida International University suggests most galaxies don’t “die” in spectacular cosmic pileups after all.
Understanding why galaxies stop forming stars is one of the biggest questions in galaxy evolution because it helps scientists explain how galaxies change over billions of years. The researchers found galaxy mergers are neither necessary nor sufficient to stop galaxies from forming new stars — a process astronomers call quenching. Instead, the findings suggest slower internal processes play a much larger role than galaxy mergers in shutting down star formation, according to Camilo Casimiro, an FIU Physics graduate student and lead author of the study that was published recently in Monthly Notices of the Royal Astronomical Society.
“I’ve always been fascinated by galaxy evolution and the question of why some galaxies continue forming stars while others stop completely,” Casimiro said.
For decades, astronomers have viewed galaxy mergers as one of the leading explanations for why otherwise active galaxies eventually stop forming new stars. The researchers set out to test a longstanding idea in astronomy known as the “merger-quasar-quench” paradigm. The theory proposes that when galaxies collide, the interaction funnels huge amounts of gas toward the galaxies’ centers, fueling supermassive black holes. Those black holes then unleash enormous amounts of energy, heating or expelling the gas needed to form stars.
It’s a dramatic theory — and one that has shaped astrophysics research for decades. Traditionally, astronomers have looked for super bright quasars, spectacular black hole outbursts and dramatic events inside a galaxy’s center, according to Asa Bluck, assistant professor of Physics, Casimiro’s advisor and coauthor of the study. However, he says what really matters is the total energy a black hole releases over billions of years — even if it’s not flashy or particularly spectacular.
The research team analyzed more than 11,000 simulated galaxies using IllustrisTNG, one of the world’s most advanced cosmological simulations. The simulation allows scientists to track billions of years of cosmic history, following how galaxies grow, collide, feed their central black holes and eventually stop forming stars. If galaxy mergers truly drove quenching, researchers expected to see galaxies stopping star formation soon after those collisions. Instead, they found that rarely happened. Only about 3% of major galaxy mergers were followed by quenching within a billion years, according to the research.
Even when researchers included all mergers — large and small — only about 12% were associated with galaxies shutting down star formation. Perhaps even more surprising, most galaxies that stopped forming stars showed no evidence of a recent merger at all.
The research is a bold endeavor for Casimiro’s first-ever peer-reviewed paper.
“Challenging a long-standing idea in galaxy evolution is something I never expected to be doing so early in my career,” he said.
“At the same time, I have a great deal of trust in my advisor and in the scientific process itself. One of the most important parts of science is being willing to test even widely accepted ideas against new data and better simulations.”
The findings don't answer what ultimately causes galaxies to stop forming stars, but they suggest astronomers may need to look beyond dramatic collisions to explain one of galaxy evolution's biggest mysteries.
Instead of asking what dramatic event ended a galaxy’s life, Casimiro says scientists may need to focus on what quietly keeps it from reigniting. It’s a shift in thinking that shows change, even on the largest scales imaginable, doesn’t usually come from a single catastrophic event — but rather from long, gradual shifts that build over time. The findings suggest that one of astronomy's biggest questions may have a less dramatic answer than scientists have long believed.
Photos and video for media use are available via Dropbox.
Journal
Monthly Notices of the Royal Astronomical Society
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Beyond the merger–quasar–quench paradigm I: mergers are neither necessary nor sufficient to quench central galaxies in illustrisTNG
COI Statement
AFLB gratefully acknowledges support from an National Science Foundation (NSF) research grant: NSF-AST 2408009. PG also acknowledges support from NSF-AST 2408009.
Cosmic gymnastics: How our Milky Way once underwent a dramatic flip
image:
Halo 18 is an example of a galaxy that had a head-on collision (see the panel at z=1.2) and had a disc flip (you can see this by comparing the disc orientation at z=1.4 and z=0). This image and Image 2 show how these two exemplary galaxies evolve with time: each panel corresponds to a different time defined by redshift (z). Redshift is a quantity used by astronomers to measure the time in the universe, with z=0 corresponding to the present day, and larger z corresponding to earlier times. Each z has two panels associated with it, which show how the galaxy looks in two planes (like the xy and xz planes in 3D space).
view moreCredit: Auriga Project
The Milky Way may have undergone a dramatic change in orientation during its history, according to new research that helps explain a long-standing mystery about our galaxy.
Using supercomputer simulations of galaxies like the Milky Way, a team of astronomers from Durham University found that galaxies with slowly rotating stellar haloes are more likely to have experienced a major 'disc flip', where the galaxy's disc changed its orientation by more than 90 degrees.
The research is being presented this week at the Royal Astronomical Society's National Astronomy Meeting in Birmingham.
Most of the Milky Way's stars are found in its flat spiral disc. Surrounding this is a much larger but much sparser stellar halo, made up mostly of stars that originally formed in smaller galaxies before being pulled into the Milky Way through galaxy mergers.
Observations from the European Space Agency's Gaia mission have shown that the Milky Way's stellar halo rotates very slowly, but astronomers have not understood why.
To investigate, the researchers analysed the evolution of 25 Milky Way-like galaxies in the Auriga suite of cosmological simulations, following their development over billions of years.
They found that galaxies with the slowest rotating stellar haloes shared two important features. They had experienced a major head-on merger with another galaxy, and they had also undergone a disc flip during their evolution.
"We already know that the Milky Way had a massive head-on collision in the past with a galaxy known as Gaia-Sausage-Enceladus (often simply called the Gaia Sausage). So, we think that the Milky Way disc likely flipped in the past," explained astronomer Kirill Batrakov, the lead researcher on the project.
The Gaia-Sausage-Enceladus was a massive dwarf galaxy that collided with and was absorbed by the early Milky Way about 10 to 11 billion years ago. This defining galactic merger was the largest event in the early history of the Milky Way and reshaped our galaxy, leaving billions of stars orbiting in highly elongated, sausage-shaped paths.
Identifying a past disc flip gives astronomers a new way to understand how the Milky Way assembled and may also provide indirect clues about the motion of its invisible dark matter halo.
"A disc flip also means most of the Milky Way's stars once moved on very different trajectories than they do today – possibly even our own Sun, meaning our 'stable' spot in the galaxy might not have been so stable for the Solar System's whole lifetime," Batrakov said.
The Milky Way is our best laboratory for testing how galaxies and dark matter evolve. A disc flip does not happen in every galaxy, so if its history included a major flip that has not been linked to observable features of our galaxy, then it offers astronomers clues about how similar galaxies formed.
"Because we live inside the Milky Way, we can study it in more detail than any other galaxy, which makes it a key testbed for understanding galaxies more broadly," Batrakov added.
"Finding that its disc flipped adds a new chapter to that story, one we must account for when placing the Milky Way in a broader context of other galaxies. What excites me the most is that this complex history can be reconstructed just from present-day observations."
Batrakov's study also found that the rotation of the Milky Way's stellar halo is closely linked to the rotation of its dark matter halo, suggesting the two possibly evolved together as the galaxy grew by accreting smaller satellite galaxies.
The findings provide a possible explanation for one of the Milky Way's unusual features and offer new clues about how our galaxy formed and evolved over billions of years.
ENDS
Images & video
Image 1: Halo 18 is an example of a galaxy that had a head-on collision (see the panel at z=1.2) and had a disc flip (you can see this by comparing the disc orientation at z=1.4 and z=0). This image and Image 2 show how these two exemplary galaxies evolve with time: each panel corresponds to a different time defined by redshift (z). Redshift is a quantity used by astronomers to measure the time in the universe, with z=0 corresponding to the present day, and larger z corresponding to earlier times. Each z has two panels associated with it, which show how the galaxy looks in two planes (like the xy and xz planes in 3D space).
https://drive.google.com/file/d/1X20dQVA3jQEWZA8nAM3JvQWE3mZIIP3i/view?usp=drive_link
Credit: Auriga Project
Image 2: Halo 6 is an opposite example: it did not have a head-on collision (for example, the collision at z=2.2 is more aligned with the orientation of its disc), and its disc did not flip. https://drive.google.com/file/d/1yV6uMyIL5izNvYWy8lI5ICEFpeROECdN/view?usp=drive_link
Credit: Auriga Project
Image 3: Artist’s impression of the merger between the Gaia-Enceladus galaxy and our Milky Way, which took place during our galaxy’s early formation stages, 10 billion years ago. Astronomers uncovered this major event in the formation history of the Milky Way after discovering an ‘odd collection’ of stars that move along elongated trajectories in the opposite direction to the majority of the galaxy’s other hundred billion stars, including the Sun. The discovery was possible thanks to the second data release of ESA’s Gaia mission and its extraordinary precision. The positions and motions of the stars in Gaia-Enceladus (represented with yellow arrows) in this early phase of the merger are based on a computer simulation that models a similar encounter to that uncovered by Gaia.
https://drive.google.com/file/d/1WrSkH2PxrrwUJ7MrEzf9OJbronvW9D66/view?usp=drive_link
Credit: ESA (artist’s impression and composition); Koppelman, Villalobos and Helmi (simulation); NASA/ESA/Hubble (galaxy image) / CC BY-SA 3.0 IGO
Image 4: Artist’s impression of debris of the Gaia-Enceladus galaxy. Yellow arrows represent the positions and motions of stars originating from Gaia-Enceladus in a simulation of a galactic merger with the Milky Way with characteristics similar to those implied by Gaia data.
https://drive.google.com/file/d/1Og9pSLpXCMoEXaY1CMhVk5StJgvVwOJo/view?usp=drive_link
Credit: ESA (artist’s impression and composition); Koppelman, Villalobos and Helmi (simulation) / CC BY-SA 3.0 IGO
Figure 1: Diagram showing the distribution of stars within the galaxy and its infalling satellite. This image shows a face-on projection; the second image (xz) shows an edge-on projection.
https://drive.google.com/file/d/1LAPkFiOkLrcxEpNl16wvws-AHbVC7dvR/view?usp=drive_link
Credit:
Figure 2: Diagram showing the distribution of stars within the galaxy and its infalling satellite. These images illustrate an edge-on projection of the ‘head-on’ collision that the galaxy underwent.
https://drive.google.com/file/d/1peDRnjjQDled7lj1GlTcfsROigIdXNJy/view?usp=drive_link
Credit:
Video 1: A video which shows the evolution of halo 18. It shows the same thing as images 1-2, but in video format.
https://drive.google.com/file/d/1upt2EJp0_onbujC5AC-_rtQeFpXz3Bxt/view?usp=drive_link
Credit: Auriga Project and Thomas Tomlinson
Further information
The talk ‘Why is the Milky Way stellar halo slowly rotating?’ will take place at NAM2026 at 15:30 BST on Tuesday 21 July 2026 in room TLC118/119. Find out more at: https://uobevents-national-astronomy-meeting-2026.eventsairsite.com/block-schedule. If you would like a Zoom link to watch it online, please email press@ras.ac.uk
Notes for editors
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