physics | College of Science

Detecting the elusive neutrino in Antarctica

October 8, 2025

Vivian O’Dell, Upgrade Project Director at the IceCube

“It’s all about the upgrade,” said Vivian O’Dell, Upgrade Project Director at the IceCube Neutrino Observatory in Antarctica. O’Dell was one of the featured speakers in the opening salvo of the IceCube Neutrino Collaboration’s semi-annual meeting, October 6-10, this year convened at the University of Utah.

The Collaboration is an international group of scientists using the IceCube Neutrino Observatory, a one-cubic-kilometer detector located in Antarctica. The site is designed to detect high-energy neutrinos from cosmic sources and to study dark matter, cosmic rays and neutrino properties.

Since its construction, which started in 2004, the IceCube Neutrino Observatory has revolutionized the field of astroparticle physics, by enabling us to observe the Universe in fundamentally new ways, using high-energy neutrinos as cosmic messengers. Most recently, in 2023, the IceCube Neutrino Observatory produced the first view of our home galaxy using high-energy neutrinos and measured neutrino properties through a phenomenon known as neutrino oscillations.

Made up of 450 people from 58 institutions in 14 countries, the Collaboration is also positioned to explore fundamental physics, and the upgrade O’Dell—based at the University of Wisconsin-Madison—was referring to is an on-going, multi-year improvement of the massive observatory. Beginning this week, Dennis Soldin from the U will take on the role of the IceCube Analysis Coordinator, coordinating the scientific data analysis efforts across all member institutions.

Adding Strings

Most recently the upgrade includes adding seven additional vertical “strings” or cables to the already existing 86. Light sensors called digital optical modules frozen into the Antarctic ice form the giant detector that uses the ice as its natural medium to detect the ghostly, electrically neutral, subatomic particle with a mass close to zero.

Once deployed, the strings are connected to the main computing facility via a surface junction box. The box is the point where the buried strings, once commissioned, link with the detector’s central data acquisition system. From there data will be analyzed by IceCube scientists and high-level data from neutrino bursts will be shared with researchers across the globe in real or close-to-real time.

Pearl Sandick, Interim Dean, College of Science

At the meeting’s opening session Monday morning at the new L. S. Skaggs Applied Science Building, O’Dell and the Detector Operations Manager Matt Kauer walked the assembled group of scientists through enhancements at the site largely focused on upgrade support and integration, including surface array improvements. IceCube Spokesperson Erin O’Sullivan reviewed the scientific program of the observatory.

Collected data on neutrinos and interactions of cosmic rays with the Earth’s atmosphere are critical to the work of particle physicists around the world including at the U where Carsten Rott, Jack W. Keuffel Memorial Chair professor and chair of the Department of Physics & Astronomy, correlates observations of high-energy neutrinos with other cosmic messengers. “To establish any correlation, it’s essential that we can accurately point back to where neutrinos originated on the sky,” said Rott in a 2023 profile about the potential of the ongoing upgrade.

“We hope that the IceCube upgrade will be just the first step towards a much larger facility for multi-messenger science at the South Pole that combines optical and radio neutrino detection with a cosmic ray air shower array.”

Utah’s Particle Detection Legacy

Rott was on hand Monday to welcome the Collaboration to the U, as was Senior Dean and Vice Provost of the Colleges of Liberal Arts & Sciences Peter Trapa who reviewed the history of astroparticle physics at the U. It began in 1959 with the arrival of Jack Koeffel whose “early detection experiments over 60 years ago,” said Trapa, “were designed to isolate the neutrino event from the other events” using what we now consider to be primitive detection systems.

In other opening remarks, particle physicist and Interim Dean of the College of Science Pearl Sandick detailed the work of the Utah Neutrino Detector with origins in a nearby 600-meter-deep Park City mine. The mine's depth provided the necessary shielding from cosmic rays, allowing scientists to focus on the rare, highly penetrating neutrino particles.

Carsten Rott, Chair, Dept. of Physics & Astronomy

Dennis Soldin, IceCube Analysis Coordinator

Known as the Spiro Tunnel, the site was intended to be a laboratory, reported the Park Record newspaper at the time, to "help probe the mysteries of outer space" by detecting neutrinos from the far reaches of the universe and Earth's atmosphere. The researchers published a paper in 1969 describing the observation of two "neutrino events" in their detector.

Despite erroneous conclusions in the paper, the experiment was considered a pioneering effort in the field of particle physics, and the U’s Cosmic Ray group, founded by Keuffel, was established. The group would ultimately include George Cassiday, Eugene Loh and Haven Bergeson. Their research in high-energy physics continued, and later projects, such as the Fly's Eye experiment in the 1980s, were built upon this early work.

More recently, Sandick reminded the group, the highest energy cosmic ray ever was detected in Utah’s Telescope Array in 1991 with the second highest energy cosmic ray detected in 2021 at the same site in the high desert of Millard County, Utah, near the town of Delta.

Public Event

With the Beehive State’s illustrious history of investigating astroparticle physics, the University of Utah is a fitting location for the IceCube Neutrino Collaboration’s meeting. And while most of the proceedings are closed to members, the U.S. premiere of “Messengers” a documentary film featuring two "winter overs" who spent an entire year in isolation at the geographic South Pole running the IceCube Neutrino Telescope experiment is open to the public on Wednesday, October 8 at the Utah Museum of Fine Art on the U campus.

The free public screening is part of the IceCube Neutrino Telescope Collaboration Meeting hosted by the Department of Physics & Astronomy and co-organized, with Rott and Soldin,

Meanwhile, the fascinating and complex upgrades to the Observatory reported on by Vivian O’Dell and others continue in Antarctica. Annually, an estimated 100,000 neutrinos will now be detected and their properties measured with what’s being called “unprecedented precision.”

by David Pace

Mysterious gamma-ray explosion unlike any discovered before

September 11, 2025

Tanmoy Laskar

Astronomers have detected an explosion of gamma rays that repeated several times over the course of a day, an event unlike anything ever witnessed before. The source of the powerful radiation was discovered to be outside our galaxy, its location pinpointed by the European Southern Observatory’s Very Large Telescope (VLT). Gamma-ray bursts (GRBs) are the most powerful explosions in the universe, normally caused by the catastrophic destruction of stars. But no known scenario can completely explain this new GRB, whose true nature remains a mystery.

GRBs are produced in catastrophic events like dying stars exploding in powerful blasts or stars being ripped apart by black holes. These celestial flashes of gamma rays usually last just milliseconds to minutes, but this signal—GRB 250702B—lasted about a day.

“This immediately alerted us to the unusual nature of this explosion,” said Tanmoy Laskar, assistant professor in the Department of Physics & Astronomy at the University of Utah and co-author of a study on this event recently published in The Astrophysical Journal Letters.

The initial alert about this GRB came on July 2, 2025, from NASA’s Fermi Gamma-ray Space Telescope. Fermi detected not one but three bursts from this source over the course of several hours. Retrospectively, it was also discovered that the source had been active almost a day earlier, as seen by the Einstein Probe, an X-ray space telescope mission by the Chinese Academy of Sciences with the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics. Such a long and repeating GRB has never been seen before.

The gamma-ray discovery only gave an approximate location in a very crowded part of the sky filled with stars from our Milky Way, making it difficult to locate the source of the flash. To pinpoint the precise position of its origin, the team turned to ESO’s VLT.

“Before these observations, the general feeling in the community was that this GRB must have originated from within our galaxy. The VLT fundamentally changed that paradigm,” said Andrew Levan, astronomer at Radboud University, The Netherlands, and co-lead author of the study.

Using the VLT’s HAWK-I camera, they found evidence that the source may actually reside in another galaxy and later confirmed this using the NASA/ESA Hubble Space Telescope.

“What we found was considerably more exciting: The fact that this object is extragalactic means that it is considerably more powerful,” said Antonio Martin-Carrillo, astronomer at University College Dublin, Ireland, and co-lead author of the study. The size and brightness of the host galaxy suggest it may be located a few billion light-years away, but more data are needed to refine this distance.

The nature of the event that caused this GRB is still unknown. One possible scenario is a massive star collapsing onto itself, releasing vast amounts of energy in the process.

“Just like other GRBs, this event also left behind lower-energy light cascading across the spectrum, all the way from X-rays to radio waves,” said Laskar. “Traditional collapsing-star models seem to be able to explain this residual, fading light, but the still-unknown distance to the event makes it difficult to be sure.”

Alternatively, a star being ripped apart by a black hole could produce a day-long GRB, but to explain other properties of the explosion would require an unusual star being destroyed by an even more unusual black hole.

To learn more about this GRB, the team has been monitoring the aftermath of the explosion with different telescopes and instruments, including the VLT’s X-shooter spectrograph and the James Webb Space Telescope, a joint project of NASA, ESA and the Canadian Space Agency. Measuring the distance to the galaxy that hosted the event will be key to deciphering the cause behind the explosion.

Adapted from the European Southern Observatory

This research was presented in the paper “The day-long, repeating GRB 250702B: A unique extragalactic transient” (doi: https://doi.org/10.3847/2041-8213/adf8e1), published in The Astrophysical Journal Letters.

Find a full list of coauthors here.

A physicist tackles machine learning black box

August 13, 2025

Zhengkang (Kevin) Zhang, assistant professor, Department of Physics & Astronomy

Despite its omnipresence in society, we’re just beginning to understand the mechanisms driving the technology. In a recent study Zhengkang (Kevin) Zhang, assistant professor in the University of Utah’s Department of Physics & Astronomy, demonstrated how physicists can play an important role in unraveling its mysteries.

“People used to say machine learning is a black box—you input a lot of data and at some point, it reasons and speaks and makes decisions like humans do. It feels like magic because we don’t really know how it works,” said Zhang. “Now that we’re using AI across many critical sectors of society, we have to understand what our machine learning models are really doing—why something works or why something doesn’t work.”

As a theoretical particle physicist, Zhang explains the world around him by understanding how the smallest, most fundamental components of matter behave in an infinitesimal world. Over the past few years, he’s applied the tools of his field to better understand machine learning’s massively complex models.

Scaling up while scaling down costs

The traditional way to program a computer is with detailed instructions for completing a task. Say you wanted software that can spot irregularities on a CT scan. A programmer would have to write step-by-step protocols for countless potential scenarios.

Instead, a machine learning model trains itself. A human programmer supplies relevant data—text, numbers, photos, transactions, medical images—and lets the model find patterns or make predictions on its own.

Throughout the process, a human can tweak the parameters to get more accurate results without knowing how the model uses the data input to deliver the output.

Machine learning is energy intensive and wildly expensive. To maximize profits, industry trains models on smaller datasets before scaling them up to real-world scenarios with much larger volumes of data.

“We want to be able to predict how much better the model will do at scale. If you double the size of the model or double the size of the dataset, does the model become two times better? Four times better?” said Zhang.

A physicist’s toolbox

A machine learning model looks simple: Input data—>black box of computing—>output that’s a function of the input.

The black box contains a neural network, which is a suite of simple operations connected in a web to approximate complicated functions. To optimize the network’s performance, programmers have conventionally relied on trial and error, fine-tuning and re-training the network and racking up costs.

“Being trained as a physicist, I would like to understand better what is really going on to avoid relying on trial and error,” Zhang said. “What are the properties of a machine learning model that give it the capability to learn to do things we wanted it to do?”

In a new paper published in the journal Machine Learning: Science and Technology, Zhang solved a proposed model’s scaling laws, which describe how the system will perform at larger and larger scales. It’s not easy—the calculations require adding up to an infinite number of terms.

The violent events of deep space

August 4, 2025

John Matthews checks on a scintillator. Credit: Mike Anderson, KSL TV.

About 1,000 square miles are covered with 60 telescope arrays, made up of specialized mirrors, and about 500 stations called scintillators.

“We don’t know what they are, but they’re big, huge, violent objects with extreme electric fields, extreme magnetic fields,” Matthews said. “And, could be something like a black hole that’s eating something, like maybe even another black hole. And it’s swirling around as it’s going in.”

Matthews said the mysterious events appear to be even more violent than a supernova. The evidence comes down in what’s called cosmic rays. They can’t be seen with the naked eye. While the hope is for the telescope arrays to capture the rays entering the atmosphere, the scintillators are there to grab what’s left as the particles spread out onto the desert surface.

“The events that you see with both detectors, that’s much more powerful, because now you can combine all this data and figure out more precisely … where did it come from,” Matthews said.

Physics Pioneer Pierre Sokolsky, Yodh Prize

July 23, 2025

Particle astrophysicists know this, and every other year the Commission on Astroparticle Physics of the International Union of Pure and Applied Physics (IUPAP) gather at the International Cosmic Ray Conference (ICRC) to recognize one of their peers with the Yodh Prize.

This year, Pierre Sokolsky, distinguished professor of physics (emeritus) at the University of Utah received the award at the the conference being held in Geneva, Switzerland.

Atmospheric fluorescence technique

The prize, which recognizes a scientist whose research career has had a major impact on the understanding of cosmic rays, was well-deserved by Sokolsky who played an instrumental role in pioneering the development of the atmospheric fluorescence technique as a method for exploring the highest energy cosmic rays. His work in understanding and verifying the extraordinary 1991 “Oh-My-God” event, observed by Utah's Telescope Array and which weighed in at 3.2x10^20 eV was pivotal.

Illustration of the Oh-my-God particle.

"Pierre’s deep understanding of cosmic ray physics, combined with his ability to communicate complex phenomena to newcomers, was invaluable to the development of the field," says John Matthews, a U colleague in the Department of Physics and Astronomy, program manager for the cosmic ray physics group and co-spokesperson of the Telescope Array project.

In fact, Sokosky's expertise, both theoretical and practical, was recognized when he was awarded the Panofsky Prize by the American Physical Society (APS) in 2008, with George Cassiday, for groundbreaking contributions to the fluorescence technique at Fly's Eye.

Named for its design, which mimicked the compound eye of an insect, the high resolution Fly's Eye was a cosmic ray observatory which used a large array of mirrors and photomultiplier tubes to detect the faint flashes of light produced when cosmic rays interact with the atmosphere. This technique, called air (or atmospheric) fluorescence—which Sokolsky helped develop, particularly in the construction of its monocular and stereo detectors—allowed scientists to study the highest energy cosmic rays. Their findings, which included the first evidence for the cosmic ray suppression and the Greisen-Zatsepin-Kuzmin (GZK) cut-off culminated, according to Matthews, in groundbreaking results that were published in Physical Review Letters in 2008.

"Pierre’s unwavering commitment to the field, his scientific acumen and his ability to foster international collaboration have made him one of the most influential figures in ultra high energy cosmic ray physics," says Matthews. "His work has significantly shaped the understanding of cosmic ray origins, and his leadership has been instrumental in producing critical results for the field."

Next phase of the Telescope Array

Yodh Prize ceremony, Geneva Switzerland.

"This award adds to the long list of recognitions that members of our department have received for their pioneering research in cosmic ray physics," says Carsten Rott, chair of Department of Physics and Astronomy and the Jack W. Keuffel Memorial Chair. Rott, speaking from the ICRC conference where the ceremony honoring Sokolsky is taking place, continues:

"This award is well deserved for Pierre and comes at a critical time where we are trying to complete the construction of the next phase of the Telescope Array cosmic ray detector (TAx4) in Utah. The importance of the anticipated data to be obtained from the completed TAx4 project was also stressed multiple times during this conference."

Gaurang Bhaskar Yodh (1928-2019) was an Indian-American physicist and an expert in astroparticle physics and cosmic-ray physics. The prize is endowed by Gaurang and his wife Kanwal to the UC Irvine Foundation which sponsors the award.

The recipient is selected on behalf of the University of California Irvine Foundation, which sponsors the accolade. In addition to a cash prize, Sokolsky is invited to give a talk at UC Irvine's Department of Physics and Astronomy.

Sokolsky, who retired from the U in 2020 is also Dean Emeritus of the College of Science at the University of Utah. Born in France, he was educated at the University of Chicago and University of Illinois. He is a Fellow of the American Physical Society.

In addition to winning the Panofsky Prize he has been a Sloan Fellow (1977), recipient of a 2006 Utah Governor's Medal for Science and Technology and was elected a Guggenheim Fellow (2020).

In 2004, he spearheaded the U’s $17 million Telescope Array Project located just west of Delta, Utah, to study ultra-high-energy cosmic rays in collaboration with scientists from the University of Tokyo Institute for Cosmic Ray Research and several other Japanese universities as well as team members from South Korea, Russia, and Belgium.

Pierre Sokolsky also launched a comprehensive astronomy research program at the U, including undergraduate and graduate degrees in astronomy.

by David Pace

Astronomers celebrate images decades in the making

July 10, 2025

Rubin Observatory Credit: H.Stockebrand

The observatory’s 8.4-meter Simonyi Survey Telescope can capture the largest field of view of any telescope currently in operation, covering the entirety of the night sky over the course of a few nights. It creates composite images approximately 70 times larger than the apparent size of the full moon. These images are 3,200-megapixel in resolution—more than 65x times more detailed than the latest iPhone.

For the U’s own astrophysics researchers, there is palpable excitement as they plan on utilizing the Rubin data for new research projects.

“We’ve all been preparing for this day, and it’s finally here! There’s already some cool science being done with just the First Look images; imagine what we can do with the full data set!” said Yao-Yuan Mao, assistant professor in the Department of Physics & Astronomy.

Mao has been involved with the Rubin research community for more than a decade, most actively in the Dark Energy Science Collaboration. The operation of the Rubin Observatory represents the culmination of years of design and planning.

“I am particularly excited about how Rubin data will enable us to find some of the smallest galaxies in our neighborhood, helping us understand how galaxies form and grow throughout the cosmic time and even reveal the nature of dark matter,” added Mao.

In addition to the ability to capture gigantic still pictures, the Rubin Observatory can also record the movements in the cosmos. The Observatory had been designed from its inception to detect up to 90% of near-Earth asteroids, advance the study of how our solar system formed, and observe phenomena such as supernovae or tidal disruption events with greater ability.

“I’m really excited for Rubin and have been looking forward to it for many years. For me, the most exciting part of Rubin will be its ability to detect tidal disruption events, which happen when a star comes too close to a massive black hole and is torn apart by the black hole’s gravity,” said Anil Seth, professor of physics and astronomy. “We have previously detected about a hundred of these events, but Rubin is predicted to detect more than 10 new tidal disruption events each night. My PhD student Christian Hannah has been working on predicting how we can use these events to understand for the first time whether small galaxies still all have massive black holes at their centers. These observations will help us understand the currently not understood formation mechanisms of the massive black holes we find at the centers of galaxies.”

The observatory honors the legacy of Vera C. Rubin, whose pioneering research on galaxy rotation produced the first accepted evidence of dark matter’s existence. All-in-all, this marks the beginning of a new and exciting era of astrophysics research. The Rubin Observatory is planned to operate for at least ten years for its Legacy Survey of Space and Time (LSST), producing hundreds of images and data for researchers and the general public.

The Rubin Observatory project was jointly funded by the U.S. National Science Foundation and the U.S. Department of Energy, Office of Science.

by Ethan Hood
This story originally appeared in @ TheU

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Hints that dark energy may evolve

March 24, 2025

DESI is an international galaxy survey experiment with more than 900 researchers from over 70 institutions around the world, including from the University of Utah, and is managed by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). The collaboration shared their findings today in multiple papers that will be posted on the online repository arXiv and in a presentation at the American Physical Society’s Global Physics Summit in Anaheim, California.

“What we are seeing is deeply intriguing,” said Alexie Leauthaud-Harnett, co-spokesperson for DESI and a professor at UC Santa Cruz. “It is exciting to think that we may be on the cusp of a major discovery about dark energy and the fundamental nature of our universe.”

The Dark Energy Spectroscopic Instrument (DESI) operating out of the Mayall 4-meter Telescope at Kitt Peak National Observatory.

Taken alone, DESI’s data are consistent with our standard model of the universe: Lambda CDM (where CDM is cold dark matter and Lambda represents the simplest case of dark energy, where it acts as a cosmological constant with constant energy density). However, when paired with other measurements, there are mounting indications that the impact of dark energy may be weakening over time and that other models may be a better fit. Those other measurements include the light leftover from the dawn of the universe (the cosmic microwave background or CMB), exploding stars (supernovae), and how light from distant galaxies is warped by gravity (weak lensing).

“We’re guided by Occam’s razor, and the simplest explanation for what we see is shifting,” said Will Percival, co-spokesperson for DESI and a professor at the University of Waterloo. “It’s looking more and more like we may need to modify our standard model of cosmology to make these different datasets make sense together—and evolving dark energy seems promising.”

So far, the preference for an evolving dark energy has not risen to “5 sigma,” the gold standard in physics that represents the threshold for a discovery. However, different combinations of DESI data with the CMB, weak lensing, and supernovae sets range from 2.8 to 4.2 sigma. (A 3-sigma event has a 0.3% chance of being a statistical fluke, but many 3-sigma events in physics have faded away with more data.) The analysis used a technique to hide the results from the scientists until the end, mitigating any unconscious bias about the data.

“We now have a better understanding of where the preference for evolving dark energy arises in the data,” said University of Utah graduate student Qinxun Li. “By comparing the distance estimates from DESI to those from less distant supernovae and the predictions from the CMB, we can illustrate how a model with time-evolving dark energy describes the data better than does the standard model for the universe.”

DESI is one of the most extensive surveys of the cosmos ever conducted. The state-of-the-art instrument can capture light from 5,000 galaxies simultaneously, and was constructed and is operated with funding from the DOE Office of Science. DESI is mounted on the U.S. National Science Foundation’s Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (a program of NSF NOIRLab) in Arizona. The experiment is now in its fourth of five years surveying the sky, with plans to measure roughly 50 million galaxies and quasars (extremely distant yet bright objects with black holes at their cores) by the time the project ends.

Mechanical technician William DiVittorio performs a carbon dioxide cleaning on the mirror of the Mayall Telescope, where DESI operates.

The new analysis uses data from the first three years of observations and includes nearly 15 million of the best measured galaxies and quasars. It’s a major leap forward, improving the experiment’s precision with a dataset that is more than double what was used in DESI’s first analysis, which also hinted at an evolving dark energy.

“These new DESI measurements are not just more precise, but have also been shown to be extremely robust. We have compared these results to previous measurements and performed new tests of internal consistency and have detected no problems in the measurements” said Li, who developed several additional quality assessment tests on the DESI data that are new relative to the first-year results.

DESI tracks dark energy’s influence by studying how matter is spread across the universe. Events in the very early universe left subtle patterns in how matter is distributed, a feature called baryon acoustic oscillations (BAO). That BAO pattern acts as a standard ruler, with its size at different times directly affected by how the universe was expanding. Measuring the ruler at different distances shows researchers the strength of dark energy throughout history. DESI’s precision with this approach is the best in the world.

The collaboration will soon begin work on additional analyses to extract even more information from the current dataset, and DESI will continue collecting data. Other experiments coming online over the next several years will also provide complementary datasets for future analyses.

“With only three years of data from DESI, we have far more precise measurements than were obtained in ten years using similar techniques in the previous galaxy survey, the Sloan Digital Sky Survey,” said Kyle Dawson, a professor in physics and astronomy at the University of Utah. Prof. Dawson was the co-spokesperson for DESI from Sept. 2020 to Aug. 2024 and was also the principal investigator for the last cosmology program within the Sloan Digital Sky Survey. “I anxiously await the results from the next few years of DESI and other cosmological programs to see if these 3-4 sigma results fade away or if indeed they stick and reveal new physics beyond what we had assumed in our standard model.”

Videos discussing the experiment’s new analysis are available on the DESI YouTube channel. Alongside unveiling its latest dark energy results at the APS meeting today, the DESI collaboration also announced that its Data Release 1 (DR1), which contains the first 13 months of main survey data, is now available for anyone to explore. With information on millions of celestial objects, the dataset will support a wide range of astrophysical research by others, in addition to DESI’s cosmology goals.

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

Story above adapted from DESI.

Gamma ray observatory gets green light

March 12, 2025

The creation of the CTAO-ERIC will enable the observatory’s construction to advance rapidly and provide a framework for distributing its data worldwide, significantly accelerating its progress toward scientific discovery. On Feb. 13, 2025, the ERIC Council approved to immediately negotiate the establishment of Japan as a strategic partner and the United States, Brazil and Australia as third-party members.

Animation of a blue light beam breaking up into multiple particles and hits Earth's atmosphere, scattering across the globe.

“This field did not exist before 1989 when the first the gamma ray source was detected. At that point, we knew of four sources in the world,” said Dave Kieda, professor in the Department of Physics & Astronomy at the University of Utah and the CTAO spokesperson for the U.S. “The past 35 years, we went from detecting the first to now seeing several hundred. With CTAO, we’re going to see thousands. And the University of Utah is part of that legacy.”

The CTAO-ERIC was established with the international support of 11 countries and one intergovernmental organization that contributed to the technological development, construction and operation of the observatory. For Kieda, the new array will give astronomers an unprecedented view of the mysterious radiation he’s spent his career studying.

“Over the last decade, people have discovered that these high energy gamma rays are present in many, many types of very energetic astronomical phenomenon, but we don’t know much about where they come from,” Kieda said.

Read the full story by Lisa Potter in @ The U. Video above: Animation of a gamma ray hitting Earth’s atmosphere, creating the blue Cherenkov light that flashes for a billionth of a second.

‘Vast discovery’ of black holes in dwarf galaxies

March 5, 2025

This dual achievement not only expands scientists’ understanding of the black hole population in the universe but also sets the stage for further explorations the formation of the first black holes to form in the universe and their role in galaxy evolution.

With DESI’s early data, the team was able to obtain an unprecedented dataset that includes the spectra of 410,000 galaxies, including roughly 115,000 dwarf galaxies—small, diffuse galaxies containing thousands to several billions of stars and very little gas. This extensive set would allow Pucha and her team to explore the complex interplay between black hole evolution and dwarf galaxy evolution.

While astrophysicists are fairly confident that all massive galaxies, like our Milky Way, host black holes at their centers, the picture becomes unclear as you move toward the low-mass end of the spectrum. Finding black holes is a challenge on its own but identifying them in dwarf galaxies is even more difficult due to their small sizes and the limited ability of our current instruments to resolve the regions close to these objects. An actively feeding black hole, however, is easier to spot.

“When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,” said Pucha. “This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.”

The study is online as a pre-print ahead of publication in The Astrophysical Journal.

Read the full story by Lisa Potter in @ The U.

Detecting the elusive neutrino in Antarctica

The U hosts the semi-annual IceCube Neutrino Collaboration

Adding Strings

Utah’s Particle Detection Legacy

Public Event

Mysterious gamma-ray explosion unlike any discovered before

No known scenario can explain the source of a recent gamma-ray burst, which originated outside our galaxy and lasted 100 to 1,000 times longer than most bursts.

A physicist tackles machine learning black box

From self-driving cars to facial recognition, modern life is growing more dependent on machine learning, a type of artificial intelligence (AI) that learns from datasets without explicit programming.

Scaling up while scaling down costs

A physicist’s toolbox

The Violent Events of Deep Space

Scientists at the University of Utah, along with others around the world, are taking a close look at deep space, with an unusual array of telescopes in the desert of Central Utah.

Physics Pioneer Pierre Sokolsky awarded the 2025 Yodh Prize

Atmospheric fluorescence technique

Next phase of the Telescope Array

Astronomers celebrate images decades in the making

On June 23 the Vera C. Rubin Observatory, located in Cerro Pachón, Chile, presented its inaugural data release of images that will drive a new generation of astrophysics research. It features first-of-its-kind technology, and the largest digital camera ever manufactured.

Spectrum 2024

Common Ground 2024

Down to Earth 2024

Our DNA 2024

Catalyst 2024

Air Currents 2024

Synthesis 2024

Aftermath 2024

Spectrum 2023

Common Ground 2023

Down to Earth 2023

Our DNA 2023

Catalyst 2023

Synthesis 2023

Aftermath Summer 2023

Air Currents 2023

Spectrum 2022

Aftermath 2022

Our DNA 2022

Spectrum 2022

Aftermath 2022

Our DNA 2022

Notebook 2022

Discover 2021

Our DNA 2021

Aftermath 2021

Spectrum 2021

Notebook 2021

Spectrum 2021

Aftermath 2021

Our DNA 2021

Discover 2020

AfterMath 2020

Our DNA 2020

Spectrum 2020

Notebook 2020

Our DNA 2020

Catalyst 2020

Spectrum 2020

Discover 2019

Spectrum 2019

Notebook 2019

Catalyst 2019

Our DNA 2019

Catalyst 2019

Spectrum 2019

Our DNA 2019

AfterMath 2018

Discover 2018

Spectrum 2018

Catalyst 2018

Hints that Dark Energy May EVOLVE

Most powerful gamma ray observatory gets green light

At the start of the year, the European Commission established the Cherenkov Telescope Array Observatory (CTAO) as a European Research Infrastructure Consortium (ERIC), furthering its mission to become the world’s largest and most powerful observatory for gamma-ray astronomy.

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‘Vast discovery’ of black holes in dwarf galaxies

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