Researchers from the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) have developed a novel machine learning framework that significantly improves the ability to solve complex differential equations, especially in cases where traditional methods struggle. The work, led by Pedro Tarancón-Álvarez and Pablo Tejerina-Pérez, has been published in Communications Physics, a journal from the Nature Portfolio. 
 

Differential equations are essential tools in physics, used to describe phenomena ranging from fluid dynamics to general relativity. However, when these equations become "stiff" (meaning they involve vastly different scales or highly sensitive parameters), they become extremely difficult to solve. This is particularly true for inverse problems, where scientists aim to deduce unknown physical laws or parameters from observed data. 
 

To tackle this challenge, the researchers have enhanced the capabilities of Physics-Informed Neural Networks (PINNs), a type of artificial intelligence that incorporates physical laws into its learning process. Their approach combines two innovative techniques:
 

• Multi-Head (MH) Training: This allows the neural network to learn a general space of solutions for a family of equations, rather than just one specific case.
• Unimodular Regularization (UR): Inspired by concepts from differential geometry and general relativity, this technique stabilizes the learning process and improves the network’s ability to generalize to new, more difficult problems.
   

These methods were successfully applied to three increasingly complex systems: the flame equation, the Van der Pol oscillator, and the Einstein Field Equations in a holographic context. In the latter case, the researchers were able to recover unknown physical functions from synthetic data, a task previously considered nearly impossible. 
 

“Recent advances in machine learning training efficiency have made PINNs increasingly popular in the past few years,” explains Pedro Tarancón-Álvarez, PhD candidate at ICCUB. “This framework offers several novel features compared to traditional numerical methods, most notably the ability to solve inverse problems.”

“Solving these inverse problems is like trying to find the solution to a problem that is missing a piece; the correct piece will have a unique solution, incorrect ones may not have a solution, or multiple ones,” adds Pablo Tejerina-Pérez, PhD candidate at ICCUB. “One could try to invent the missing piece of the problem and then see if it can be solved properly – our PINNs do the same, but in a much smarter and efficient way than us.” 
 

The research was carried out in collaboration with Raul Jimenez (ICREA-ICCUB) and Pavlos Protopapas (Harvard University) and was supported by the Spanish Ministry of Science and Innovation and the Maria de Maeztu Excellence Program. 
 

Reference:

Tarancón-Álvarez, P., Tejerina-Pérez, P., Jimenez, R. et al. Efficient PINNs via multi-head unimodular regularization of the solutions space. Commun Phys 8, 335 (2025). https://doi.org/10.1038/s42005-025-02248-1

Xavier Luri Carrascoso is now officially the new director of the Institute of Space Studies of Catalonia (IEEC). Since September 1st, Luri has taken over from the previous director, Ignasi Ribas Canudas, who led the Institute from 2017 to 2025.

 Xavier Luri (Ribes de Freser, Girona, 1966) holds a PhD in Physics from the University of Barcelona, where he has been a professor in the Department of Quantum Physics and Astrophysics since 2021. In addition to his teaching career, which began in the early 1990s, Luri has built a solid research career at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), one of the research units that make up the IEEC.

Since 2023, he has been a member of the European Space Sciences Committee, an institution that provides independent scientific advice on space science to entities such as the European Commission (EC) and the European Space Agency (ESA). His scientific activity is closely tied to ESA, as it mainly focuses on the Gaia mission, an astrometric satellite built by ESA with ICCUB and IEEC participation, designed to create the largest and most precise 3D map of our galaxy by observing over a billion stars.

Luri was one of the original proponents of the Gaia mission for its approval by ESA in 2001 and was a member of its scientific advisory group, the Gaia Science Team (2001–2007). Since 2014, he has played a key role in Spain’s contribution to the project, participating in research and development related to supercomputing, data processing, software development, and the calibration of luminosity, kinematics, and galactic dynamics.

Luri also has extensive experience in innovation and knowledge transfer. During the development phase of the Gaia mission, he participated in ESA development contracts that led to a patent for a data compression system and the creation of the spin-off company DAPCOM, of which he is a founder.

In addition to his research and innovation work, Luri has shown a strong commitment to science outreach, actively working to bring space science closer to society. Throughout his career, he has participated in numerous activities such as talks, workshops, and astronomical observations, and has led successful outreach projects like co-founding the Big Van Ciencia association.

In this new phase as director of the IEEC, Xavier Luri will lead the Institute’s strategy to continue positioning it as a reference institution in scientific research, technological development and innovation, and in promoting the space sector in Catalonia. The IEEC plays a key role in the implementation of Catalonia’s NewSpace Strategy, driven by the Government of the Generalitat.

“It is an honor to have been chosen as the new director of the IEEC”, says Xavier Luri, as he thanks Ignasi Ribas for the work that has turned the Institute “into the great center that it currently is.” Luri’s goal will be to continue strengthening the role of the IEEC as a reference center in space research and industry in Catalonia, while opening it up to new challenges through its constituent units.

Heartfelt thanks from ICCUB

From the Institute of Cosmos Sciences of the University of Barcelona, we wish to express our deepest gratitude to Dr. Xavier Luri Carrascoso for his dedication, commitment, and leadership over the years as director of our institute.

His vision, drive, and teamwork have been fundamental in growing ICCUB and consolidating it as a national and international research leader. It has been a privilege to walk alongside him, learning from his generous and inspiring approach.

As he begins this new chapter as director of the IEEC, we wish him every success and happiness in this new challenge. We are confident he will continue to leave a lasting mark, as he has with us, and will keep contributing with passion and excellence to the world of space science.

Astronomers have used observatories around the world, including the European Southern Observatory's Very Large Telescope (ESO’s VLT), to study the asteroid 1998 KY26, revealing it to be almost three times smaller and spinning much faster than previously thought. The asteroid is the 2031 target for Japan’s Hayabusa2 extended mission. The new observations offer key information for the mission’s operations at the asteroid, just six years out from the spacecraft’s encounter with 1998 KY26.

This animation shows the touchdown manoeuvre that Japan’s Hayabusa2 spacecraft is likely to perform when it reaches its target in 2031, in a brief encounter with the asteroid 1998 KY26. Now that a new study has shown that this asteroid is roughly three times smaller than previously expected, and spinning twice as fast, this procedure may be more difficult to conduct. Credit: ESO/M. Kornmesser. Asteroid: T. Santana-Ros et al. Hayabusa2 model: SuperTKG (CC-BY-SA).

“We found that the reality of the object is completely different from what it was previously described as,” says astronomer Toni Santana-Ros, a researcher from the University of Alicante and the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), Spain, who led a study on 1998 KY26 published today in Nature Communications. The new observations, combined with previous radar data, have revealed that the asteroid is just 11 metres wide, meaning it could easily fit inside the dome of the VLT unit telescope used to observe it. It is also spinning about twice as fast as previously thought: “One day on this asteroid lasts only five minutes!" he says. Previous data indicated that the asteroid was around 30 metres in diameter and completed a rotation in 10 minutes or so. 

"The smaller size and faster rotation now measured will make Hayabusa2’s visit even more interesting, but also even more challenging,” says co-author Olivier Hainaut, an astronomer at ESO in Germany. This is because a touchdown manoeuvre, where the spacecraft ‘kisses’ the asteroid, will be more difficult to perform than anticipated. 

1998 KY26 is set to be the final target asteroid for the Japanese Aerospace eXploration Agency (JAXA)'s Hayabusa2 spacecraft. In its original mission, Hayabusa2 explored the 900-metre-diameter asteroid 162173 Ryugu in 2018, returning asteroid samples to Earth in 2020. With fuel remaining, the spacecraft was sent on an extended mission until 2031, when it’s set to encounter 1998 KY26, aiming to learn more about the smallest asteroids. This will be the first time a space mission encounters a tiny asteroid — all previous missions visited asteroids with diameters in the hundreds or even thousands of metres. 

Santana-Ros and his team observed 1998 KY26 from the ground to support the preparation of the mission. Because the asteroid is very small and, hence, very faint, studying it required waiting for a close encounter with Earth and using large telescopes, like ESO’s VLT in Chile’s Atacama Desert. 

The observations revealed that the asteroid has a bright surface and likely consists of a solid chunk of rock, which may have originated from a piece of a planet or another asteroid. However, the team could not completely rule out the possibility that the asteroid is made up of rubble piles loosely sticking together. “We have never seen a ten-metre-size asteroid in situ, so we don't really know what to expect and how it will look,” says Santana-Ros, who is also affiliated with the University of Barcelona. 

“The amazing story here is that we found that the size of the asteroid is comparable to the size of the spacecraft that is going to visit it! And we were able to characterise such a small object using our telescopes, which means that we can do it for other objects in the future,” says Santana-Ros. “Our methods could have an impact on the plans for future near-Earth asteroid exploration or even asteroid mining.” 

“Moreover, we now know we can characterise even the smallest hazardous asteroids that could impact Earth, such as the one that hit near Chelyabinsk, in Russia in 2013, which was barely larger than KY26,” concludes Hainaut.

More information

This research was presented in a paper titled “Hayabusa2♯ mission target 1998 KY26 preview: decametre size, high albedo and rotating twice as fast” to appear in Nature Communications (doi: 10.1038/s41467-025-63697-4). 

The team is composed of T. Santana-Ros (Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Spain), P. Bartczak (Instituto Universitario de Física Aplicada a las Ciencias y a las Tecnologías, Universidad de Alicante, Spain and Astronomical Observatory Institute, Faculty of Physics and Astronomy, A. Mickiewicz University, Poland [AOI AMU]), K. Muinonen (Department of Physics, University of Helsinki, Finland [Physics UH]), A. Rożek (Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, UK [IfA UoE]), T. Müller (Max-Planck-Institut für extraterrestrische Physik, Germany), M. Hirabayashi (Georgia Institute of Technology, United States), D. Farnocchia (Jet Propulsion Laboratory, California Institute of Technology, USA [JPL]), D. Oszkiewicz (AOI AMU), M. Micheli (ESA ESRIN / PDO / NEO Coordination Centre, Italy), R. E. Cannon (IfA UoE), M. Brozovic (JPL), O. Hainaut (European Southern Observatory, Germany), A. K. Virkki [Physics UH], L. A. M. Benner (JPL), A. Cabrera-Lavers (GRANTECAN and Instituto de Astrofísica de Canarias, Spain), C. E. Martínez-Vázquez (International Gemini Observatory/NSF NOIRLab, USA), K. Vivas (Cerro Tololo Inter-American Observatory/NSF NOIRLab, Chile). 

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society. 

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Contacts

Toni Santana-Ros
Planetary Scientist, University of Alicante and University of Barcelona
Alicante and Barcelona (Catalonia), Spain
Tel: +34 965903400 Ext: 2645 / 600948703
Email: tsantanaros@icc.ub.edu

Olivier Hainaut
ESO Astronomer
Garching bei München, Germany
Tel: +49 89 3200 6754
Cell: +49 151 2262 0554
Email: ohainaut@eso.org

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
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Cell: +49 151 241 664 00
Email: press@eso.org

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For centuries, astronomers have puzzled over the origins of one of the universe’s oldest and densest stellar systems, known as globular clusters. Now, a University of Surrey-led study published in Nature has finally solved the mystery using detailed simulations – while also uncovering a new class of object that could already be in our own galaxy. 

Globular clusters are dense collections of hundreds of thousands to millions of stars found orbiting around galaxies, including the Milky Way. Unlike galaxies, they show no evidence of dark matter, and their stars are unusually uniform in age and chemical composition – traits that have left scientists debating their formation since their discovery in the 17th century. 

Surrey researchers used ultra-high-resolution simulations that can trace the Universe’s 13.8-billion-year history in unprecedented detail, allowing them to watch globular clusters form in real-time within their virtual cosmos, called EDGE. The simulations find multiple pathways for their creation and, unexpectedly, the emergence of a new class of star system – “globular cluster-like dwarfs” – that sits between globular clusters and dwarf galaxies in terms of their properties.  

Dr Matt Orkney, Postdoctoral researcher at the University of Barcelona's Institute of Cosmos Sciences, said: 

“The origin of globular clusters has long puzzled astrophysicists. The EDGE simulations represent a major leap in understanding the diverse pathways of their formation, including clusters born in the violent interactions between merging galaxies, and those formed within their own dark matter structures.” 

Working in collaboration with Durham University, the University of Bath, the University of Hertfordshire, Carnegie Observatories and the American Museum of Natural History in the USA, Lund University in Sweden and the University of Barcelona in Spain, researchers used the UK’s DiRAC National Supercomputer facility to run the EDGE simulations over several years. To put the scale into perspective, if the largest simulations were run on a standard or high-end laptop, they would take decades to complete. These simulations not only recreated realistic globular clusters and dwarf galaxies but also predicted a previously unknown class of object.  

Conventional dwarf galaxies are typically dominated by dark matter, with around a thousand times more of the mysterious substance than stars and gas combined. However, the newly identified ‘globular cluster-like dwarfs’ appear similar to regular star clusters when observed, yet still contain a significant amount of dark matter – meaning telescopes may have already found them in the real universe and classified them as regular globular clusters. This small difference would place them in a unique position to study both dark matter and cluster formation. 

Several known Milky Way satellites, such as the “ultra-faint” dwarf galaxy Reticulum II, are likely candidates. If confirmed, they could become prime sites for the search for pristine, metal-free stars born in the early Universe and new locations to test models for the ever-elusive “dark matter”. 

Professor Justin Read, Chair of Astrophysics at the University of Surrey, said: 

“The EDGE project set out to build the most realistic simulation of the very smallest galaxies in the Universe – one that could follow all 13.8 billion years of its history while still zooming in on the tiny details, like the blast from a single exploding star. It took years to run on the UK’s DiRAC National Supercomputer, but the payoff has been extraordinary. At a resolution of just 10 light years, fine enough to capture the effects of individual supernovae, we’ve been able to show that globular clusters can form in at least two different ways, both without dark matter.” 

The next step is to confirm the existence of these globular cluster-like dwarfs through targeted observations with telescopes, including the James Webb Space Telescope and upcoming deep spectroscopic surveys. If they do, it could give astronomers new ways to test dark matter theories and offer some of the best chances to find the Universe’s very first generation of “metal-free” stars. 

• The full paper can be found: https://www.nature.com/articles/s41586-025-09494-x (10.1038/s41586-025-09494-x)

Massive stars in metal-poor galaxies often have close partners, just like the massive stars in our metal-rich Milky Way. This is discovered by an international team of seventy astronomers led by scientists from Belgium, the Netherlands, and Israel and including ICREA Professor Mark Gieles, Spain. They used the European Very Large Telescope in Chile to monitor the velocity of massive stars in the Small Magellanic Cloud. The researchers will publish their findings Tuesday in Nature Astronomy.

For the past twenty years, astronomers have known that many massive stars in the metal-rich Milky Way have a partner. In recent years, it has become clear that the interaction between these partners is important for the evolution of massive stars. However, until now, astronomers were unsure if massive stars in metal-poor galaxies, could also be part of a binary system. Now, it turns out that this is indeed the case.

Time machine
"We used the Small Magellanic Cloud as a time machine," explains Hugues Sana from KU Leuven (Belgium). "The Small Magellanic Cloud has a metallicity environment representative of that of distant galaxies when the Universe was only a few billion years old."

Studying massive stars outside of the Milky Way is difficult because the stars are far away and we receive little light from them. The researchers used the FLAMES spectrograph on the Very Large Telescope of the European Southern Observatory in Chile. It is one of the largest telescopes on Earth. FLAMES has 132 fiber optics, each of which can be directed at a different star, which can then be observed simultaneously.

Accelerate and decelerate
Over a period of 3 months, the researchers observed the acceleration and deceleration of 139 massive O-type stars at 9 different times. These stars have masses between 15 and 60 times that our our Sun. They are hot, shine brightly, and end their lives in supernova explosions. In the process, the star's core collapses into a black hole. The results show that over 70 percent of the observed stars accelerates and decelerates. That is a sign for a nearby partner.

"The fact that massive stars in the Small Magellanic Cloud have a partner suggests that the first stars in the universe, which we suspect were also massive, had partners, too," says co-author Julia Bodensteiner of the University of Amsterdam (the Netherlands). "Perhaps some of those systems end up as two black holes orbiting each other. It’s an exciting thought."

The researchers have planned to observe the same stars sixteen more times in the near future. They aim to reconstruct the precise orbits of the binary stars, determine the masses of their components, and study the nature and properties of the companion star.

"Using our measurements, cosmologists and astrophysicists studying the young, metal-poor universe will then be able to rely on our knowledge of massive binary stars with greater confidence," concludes the Tomer Shenar of Tel Aviv University (Israel). Mark Gieles, ICREA Research Professor at the Institute of Cosmos Sciences of the University of Barcelonas (Spain), notes that “knowing the properties of massive binary stars at low metallicity is of great importance for our understanding of the origin of gravitational wave sources.”

Scientific paper
A high fraction of close massive binary stars at low metallicity. By: Hugues Sana, Tomer Shenar, Julia Bodensteiner, et al. In: Nature Astronomy, 2 September 2025. [original | preprint (pdf)]

In exactly one year, on 12 August 2026, Catalonia will witness a total solar eclipse, an exceptional astronomical event not seen in the country for more than a century. The path of totality will cross the south of Catalonia, offering a unique scientific, educational, and social opportunity for the region. This year, 12 August 2025 will be an ideal date to check whether your chosen observation spot provides a clear, unobstructed view of the sunset.

The scope of this event has led to the creation of the Interdepartmental Commission on the Eclipse, within the framework of the CIRI (Interdepartmental Commission for Research and Innovation), chaired by the President of the Government of Catalonia, Salvador Illa. This commission, headed by the Minister for Research and Universities, Núria Montserrat, brings together thirteen government departments and has the scientific and technical support of the Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya)  and other leading centres in astronomical research and space observation. Its aim is to coordinate the actions of the various departments and ensure a joint, well-planned, and ambitious response to an event that goes beyond the scientific sphere to become a true national project.

Since its formation in May 2025, the commission has activated a wide range of key measures covering territorial planning, mobility, safety, public health, education, tourism, and scientific outreach. Notable initiatives include the development of a visibility map for the eclipse, the identification of safe and accessible observation areas, and the upcoming rollout of educational and public awareness programmes across the country. The aim is to ensure a safe, inclusive, and enriching experience for everyone.

Among the significant actions taken so far, the Department of Research and Universities has held coordination meetings with the National Eclipse Commission, with the goal of aligning territorial strategies with state guidelines and ensuring efficient event management. A first series of meetings has also been held with major Catalan astronomy associations, with the aim of integrating their expertise and local presence into outreach and citizen engagement efforts. These organisations will be key players in spreading knowledge about the eclipse throughout the country and enabling a shared, safe, and informed experience of the event.

In the words of the Minister for Research and Universities, Núria Montserrat: “A total solar eclipse is a scientific and collective gift that only happens once every many generations. Our duty is to organise it well so that everyone can enjoy it safely, from any point in the territory. Coordinating an event like the eclipse means working side by side with many different stakeholders. The challenge is to ensure that all the pieces fit together so that the public can enjoy it with safety, quality, and the scientific guidance it deserves.” She adds: “We want Catalonia to experience something truly unique on 12 August 2026: with eyes turned to the sky, but also with feet firmly on the ground, always following the safe observation guidelines we are preparing.”

At the same time, technical teams are already working on producing a visibility map (a “shadow map”) that will identify areas of the territory where observation conditions will be optimal, without obstructions to the view of the Sun at the critical moment. This resource will be made available in the coming months as a reference tool for institutions, organisations, and the general public.

In addition to the technical and coordination measures, an official website is being developed to serve as the institutional reference point for the eclipse. This digital platform will gather all relevant information about the event: safe observation tips, educational and outreach resources, scheduled activities across the territory, as well as visibility maps and other useful tools for citizens, schools, local councils, and media outlets. The website will be launched in the coming months and will be regularly updated until the eclipse takes place.

Where will the eclipse be visible from?

One of the commission’s top priorities is the identification of safe and accessible locations from which to observe the eclipse. Since the phenomenon will occur in the evening—between 19:30 and 21:00, with the total phase expected around 20:30 depending on location—the Sun will be very close to the horizon. This factor may limit visibility depending on the terrain and the presence of natural or human-made obstacles.

To support local planning efforts, the Rural Agents Corps, under the Department of Interior and Public Safety,will carry out an initial round of site visits on 12 August to assess various potential observation points along the path of totality. These on-site inspections will help determine horizon visibility and assess accessibility and safety conditions. The findings will contribute to a preliminary inventory of optimal viewing locations and help guide environmental, logistical, and preventive measures.

That same day, 12 August 2025, is also a great opportunity for the public to conduct their own visibility check. From the location where you hope to watch the eclipse next year, simply observe whether the sunset can be seen without any obstructions. If it can, it is highly likely that this spot will also offer a good view of the astronomical phenomenon. This simple step is a great way to start preparing for the event safely and in advance.

“This Tuesday 12 August we have a very good excuse to go out and enjoy the sunset. If we manage to see it without obstruction from somewhere within the path of totality, we will have found a good spot for observing next year’s eclipse,” explains Ignasi Ribas, director of the IEEC and researcher at the Institute of Space Sciences (ICE-CSIC). He adds: “Moreover, the next total solar eclipse visible from anywhere in Catalonia will be on 17 November 2180, so we must make the most of next year’s opportunity to see a total eclipse from our own land, without having to wait more than 150 years!”

A unique opportunity for knowledge and the country

Total solar eclipses are of great scientific interest and present an excellent opportunity to promote scientific culture. For this reason, the Government plans to roll out a coordinated outreach strategy with key research institutions such as the Ebre Observatory, the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), and the Institute of Space Sciences (ICE-CSIC). Furthermore, the event has the potential to act as a catalyst for regional development through astrotourism and the launch of new educational and community-based projects.

Catalonia is preparing to welcome the eclipse with a national outlook—grounded in science and education, but also in responsibility, sustainability, and social cohesion. On 12 August 2026, the sky will darken for a few moments. And the entire territory will be ready to look up.

An international team of scientists has announced groundbreaking observations of the brightest gamma-ray burst (GRB) ever recorded, GRB 221009A. The findings, published today in The Astrophysical Journal Letters, provide the strongest evidence yet for the existence of complex, structured jets in long-duration GRBs, cosmic explosions among the most powerful events in the Universe. 

The researchers are members of the CTAO LST Collaboration, a global scientific project dedicated to advancing very-high-energy gamma-ray astronomy. The Collaboration brings together experts from over 11 countries to design, build, and operate the Large-Sized Telescopes (LSTs) of the Cherenkov Telescope Array Observatory (CTAO), the next-generation facility for exploring the most extreme phenomena in the Universe.

GRB 221009A, dubbed the “BOAT” (Brightest Of All Time), was first detected on October 9, 2022, by space-based observatories including NASA’s Fermi and Swift satellites. The burst was so intense that it saturated detectors and triggered follow-up observations across the globe.

The LST-1 telescope, located at the CTAO’s northern site in La Palma, began observing the event just 1.33 days after the initial explosion—making it the earliest ground-based observations of very-high-energy gamma rays from this event by an imaging atmospheric Cherenkov telescope. These instruments detect gamma rays indirectly by capturing the brief flashes of light produced when these rays interact with the Earth’s atmosphere. Despite challenging conditions due to moonlight, the team was able to record an excess of gamma-ray events from GRB 221009A, making it a rare and valuable finding in this energy range.

A new window into Cosmic Jet physics

What makes this discovery particularly exciting is its contribution to our understanding of GRBs, how they operate and emit such colossal amounts of energy. The data from LST-1 support the theory that GRB 221009A was powered by a structured jet, a narrow, ultra-fast core surrounded by a slower, wider wing. This contrasts with the simpler “top-hat” jet models commonly used to describe GRBs.

“GRB 221009A provides strong evidence for a structured jet in long GRBs” said Arnau Aguasca-Cabot, predoctoral researcher at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) and the Institute of Spaces Studies of Catalonia (IEEC) and coordinator of the study. “its detection has significant implications for theoretical models of jets.”

The LST-1 observations also help distinguish between competing theoretical models. Some predicted much higher very-high-energy gamma-ray emission than was observed. The new data rule out those models, narrowing the field and guiding future research.

“Unique events like this GRB, which challenge theoretical models, may reveal insights into the unknown nature of the central engine powering this cosmic jet", said Pol Bordas, ICCUB-IEEC researcher and co-author of the study.

A Milestone for the CTAO and High-Energy Astrophysics

This campaign marks the most extensive GRB follow-up ever conducted by LST-1, spanning over 20 days. It also demonstrates the telescope’s ability to operate under moonlight conditions—an important step in increasing the observatory’s responsiveness to transient cosmic events.

“We conducted the first analysis under moonlight conditions, setting a key precedent for rapid follow-up of transient events when timely data collection is critical”, said Monica Seglar Arroyo, IFAE researcher and coordinator of the study. 

These results highlight the power of the CTAO’s next-generation telescopes to explore the high-energy Universe, since we’re entering a new era where we can probe the inner workings of cosmic explosions in unprecedented detail.

As the CTAO continues to expand, with more telescopes becoming operative in both hemispheres, scientists anticipate even more rapid and sensitive observations of GRBs and other extreme phenomena.

About the LST

The Large-Sized Telescopes (LSTs) are one of the three types of telescopes that the CTAO will use to cover its broad energy range, from 20 GeV to 300 TeV. When gamma rays interact with Earth’s atmosphere, they generate cascades of particles that produce Cherenkov light. Because lower-energy gamma rays create only small amounts of Cherenkov light, telescopes with large collection areas are needed to detect it. The LST, with its 23-meter diameter dish, will provide the CTAO’s unique sensitivity in the low-energy range between 20 and 150 GeV.

Despite standing 45 meters tall and weighing 100 tonnes, each LST can reposition to any point in the sky within 20 seconds. Both this rapid repositioning and the low-energy threshold of the LSTs are critical for the CTAO’s studies of galactic transients, high-redshift active galactic nuclei, and gamma-ray bursts.

The CTAO LST Collaboration, responsible for designing and building these telescopes, is making rapid progress on the CTAO-North site in La Palma, Spain. In 2018, the LST prototype, LST-1, was inaugurated and has been under commissioning since then. Currently, three additional LSTs are under construction and are expected to be complete by spring 2026.

About the CTAO

The CTAO (Cherenkov Telescope Array Observatory; www.ctao.org) will be the world’s largest and most powerful observatory for gamma-ray astronomy. The CTAO’s unparalleled accuracy and broad energy range (20 GeV- 300 TeV) will help to address some of the most perplexing questions in astrophysics, falling under three major themes: understanding the origin and role of relativistic cosmic particles; probing extreme environments, such as black holes or neutron stars; and exploring frontiers in physics, searching for dark matter or deviations from Einstein’s theory of relativity. Additionally, the CTAO will play a key role in both multi-wavelength and multi-messenger fields in the coming decades thanks to its enhanced performance, which will allow it to provide fundamental gamma-ray information in the quest to probe the most extreme scenarios.

To cover its broad energy range, the CTAO will use three types of telescopes: the Large-Sized Telescopes (LST), the Medium-Sized Telescopes (MST) and the Small-Sized Telescopes (SST). More than 60 telescopes will be distributed between two telescope array sites: CTAO-North in the northern hemisphere at the Instituto de Astrofísica de Canarias’ (IAC’s) Roque de los Muchachos Observatory on La Palma (Spain), and CTAO-South in the southern hemisphere at the European Southern Observatory’s (ESO’s) Paranal Observatory in the Atacama Desert (Chile). The Headquarters of the CTAO is hosted by the Istituto Nazionale di Astrofisica (INAF) in Bologna (Italy), and the  Data Management Centre (SDMC) Data Management Centre (SDMC) is hosted by the Deutsches Elektronen-Synchrotron DESY in Zeuthen (Germany).

The CTAO is a Big Data project. The Observatory will generate hundreds of petabytes (PB) of data in a year (~12 PB after compression). Based on its commitment to open science, the CTAO will be the first gamma-ray observatory of its kind to operate as an open, proposal-driven observatory providing public access to its high-level science data and software products.

In January 2025, the CTAO was established as a European Research Infrastructure Consortium (ERIC) by the European Commission. The Founding Members of the CTAO ERIC are Austria, the Czech Republic, the European Southern Observatory (ESO), France, Germany, Italy, Poland, Slovenia, and Spain. Additionally, Japan is a Strategic Partner, and the accession of Switzerland and Croatia as Founding Members is being processed. 

The CTAO ERIC, commonly referred to as the CTAO Central Organisation, is in charge of the construction and operations of the Observatory. This group works in close cooperation with partners from around the world toward the development of the Observatory. Major partners include In-Kind Contribution Collaborations that are developing essential hardware and software, in addition to the  CTAO Consortium, an international group of researchers who works in the scientific exploitation of the Observatory.

Reference

K. Abe et al. (2025). GRB 221009A: Observations with LST-1 of CTAO and implications for structured jets in long gamma-ray bursts. The Astrophysical Journal Letters. https://doi.org/10.3847/2041-8213/ade4cf

Media Contact:

Prof. Masahiro Teshima
LST Principle Investigator (PI)
mteshima@icrr.u-tokyo.ac.jp
(English, Japanese)

LST Outreach Team
lst-outreach@cta-observatory.org
(English, Spanish, German and Croatian)

Dr. Alba Fernández-Barral
CTAO Outreach, Education and Communication Officer
alba.fernandezbarral@cta-observatory.org
+39-051-6357-270
(English, Spanish and Italian)
 

The Institute of Cosmos Sciences of the University of Barcelona (ICCUB) has received the prestigious María de Maeztu Unit of Excellence accreditation by the Spanish State Research Agency (AEI), under the Ministry of Science, Innovation and Universities.
 

The recognition was officially presented last Wednesday during a ceremony held at the University of Zaragoza, which was attended by the Minister of Science, Innovation and Universities, Diana Morant; the Minister of Education, Vocational Training and Sports, Pilar Alegría; the President of the Higher Council for Scientific Research, Eloísa del Pino; the Vice-Rector for Scientific Policy, Pilar Pina Iritia; the Vice-Rector for Innovation, Transfer and Continuing Education, Manuel Gonzalez Badía, both from the University of Zaragoza; and the Director of the State Research Agency, José Manuel Fernández de Labastida.
 

The accreditation includes a 2.25 million euro grant over four years, aimed at strengthening the institute’s strategic research programs and talent development.

Prof. Licia Verde, Scientific Director of ICCUB, accepted the award on behalf of the institute, underscoring the collective effort and dedication of the entire research team.
 

ICCUB is one of only eight research units across Spain to receive this distinction in 2024, which reinforces its role as a leading center for fundamental research and innovation in astrophysics, particle physics and cosmology, and supports its mission to advance knowledge and train the next generation of scientists.

“Severo Ochoa” Excellence Centres:

• Institut de Física d’Altes Energies (IFAE).
• Institut Català d’Investigació Química (ICIQ).
• Barcelona School of Economics (BSE).
• Instituto de Ciencias Fotónicas (ICFO).
• Instituto de Ciencias del Mar (ICM-CSIC).
• Centro Nacional de Investigaciones Oncológicas (CNIO).
•  Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC).
• Fundación Donostia International Physics Center (DIPC).
• Estación Biológica de Doñana (EBD).
   

“María de Maeztu” Excellence Units:

• Departamento de Medicina y Ciencias de la Vida (MELIS), de la Universidad Pompeu Fabra.
• Institut de Ciencies del Cosmos (ICCUB), de la Universidad de Barcelona.
• Institut de Ciencia i Tecnologia Ambientals (ICTA), de la Universidad Autónoma de Barcelona.
• Institut Català de Paleoecologia Humana i Evolució Social (IPHES), de la Universidad de Barcelona.
• Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), de la Universidad de Santiago de Compostela.
• Instituto de Ciencia Molecular (ICMOL), de la Universidad de Valencia.
• Instituto Universitario de Investigación de Matemáticas (IMUS), de la Universidad de Sevilla.
• Fundación IMDEA Software.

Key Figures from the 2024 Call:
 

• 17 institutions accredited: 9 Severo Ochoa Centers and 8 María de Maeztu Units
• 60% success rate for Severo Ochoa applications, 15% for María de Maeztu
• 35% of scientific directors and 32% of principal investigators are women
• Accredited institutions hold 88 National Research Awards, 20 active ATRAEs, and 40% of all ERC grants in Spain
• Catalonia leads in number of accredited institutions, followed by Madrid and Andalusia

For more information, visit the AEI website.

Since the announcement on July 1, 2025, of the discovery of a new interstellar object—the third of its kind known to date—astronomers from Michigan State University (MSU), along with an international team of researchers including Toni Santana-Ros from the Institute of Applied Physics to Science and Technology at the University of Alicante (UA) and the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), have focused their efforts on collecting data about this exotic body.

The team has now published the first scientific article on what is currently known about the object named 3I/ATLAS, in honor of the telescope network that discovered it: NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS). ATLAS consists of four telescopes—two in Hawaii, one in Chile, and one in South Africa—that automatically scan the entire sky several times each night in search of moving objects.

According to Santana-Ros, “the object is far from Earth, at 3 astronomical units, which is about 500 million kilometers, and its trajectory poses no risk of impact with our planet.”

As noted in the article, experts confirm that 3I/ATLAS is only the third interstellar object detected passing through the solar system. It may emit gas like other comets, although this is yet to be confirmed. Among other data, they also report that it is moving at a staggering speed of 216,000 km/h relative to the Sun and follows a boomerang- or hyperbola-shaped orbital path, which will lead it to exit the solar system and never return.

Astronomers hope that the James Webb Space Telescope and the Hubble Space Telescope will reveal more information about its size, composition, rotation, and how it reacts to the increasing solar radiation it will receive in the coming months.

UA and ICCUB researcher and co-author of the article, who has been actively involved in tracking 3I/ATLAS, explains that “studying interstellar objects that come from outside our solar system is an opportunity to advance our understanding of how planetary systems form and evolve.”

In addition to MSU and UA, the research and article involve collaboration from the European Space Agency’s Near-Earth Object Coordination Centre (Italy), NASA/Caltech’s Jet Propulsion Laboratory (USA), University of Hawaii (USA), Auburn University (USA), University of Barcelona (Spain), European Southern Observatory (Germany), Villanova University (USA), Lowell Observatory (USA), University of Maryland (USA), Las Cumbres Observatory (USA), University of Belgrade (Serbia), Polytechnic University of Milan (Italy), University of Michigan (USA), Western University (Canada), Georgia Institute of Technology (USA), Diego Portales University (Chile), and Boston University (USA).

Reference:
Darryl Z. Seligman et al., “Discovery and Preliminary Characterization of a Third Interstellar Object: 3I/ATLAS”, arXiv (2025). DOI: 10.48550/arxiv.2507.02757

Source: Michigan State University / UA Communications Unit

Media Contact:
Toni Santana-Ros, researcher at the Institute of Applied Physics to Science and Technology at UA and ICCUB: antonio.santana@ua.es