physics-news

Cosmic Ray on SciFri

December 18, 2023

Sci Fri: Cosmic Ray Burst

Around 30 years ago, scientists in Utah were monitoring the skies for cosmic rays when they detected a surprising particle. It struck the atmosphere with much more energy than they had previously seen—enough energy to cause the researchers to dub it the “Oh My God Particle.”

 

John N. Matthews of the U's Department of Astronomy and Physics, standing beside large telescope mirrors at the Telescope Array Project's florescence detector station just outside the Drum Mountains, Millard County, Utah. Photo by Joe Bauman, May 25, 2013. Banner Photo above: The surface detector array of the Telescope Array experiment, deployed by helicopter. Credit: Institute For Cosmic Ray Research, University Of Tokyo

Over the years, a collaboration of researchers in Utah and Japan has detected other powerful rays—about 30 a year—but none that rival the OMG. In 2021, however, a second particle was detected. It was only slightly less powerful than OMG, but still many times more powerful than can be created on Earth. That 2021 particle was named “Amaterasu,” after a sun goddess from the Japanese Shinto religion. The researchers described their observations in a recent issue of the journal Science.

The researchers believe the particle must have come from relatively nearby, cosmically speaking, as otherwise it would likely have collided with something in space and lost its energy. However, when they tried to trace the particle back to its origin in space, they were unsuccessful. Both the OMG particle and the new Amaterasu particle seem to have come from empty regions of space, with no violent events or massive structures to create them.

Dr. John Matthews, a research professor in physics and astronomy and manager of the Cosmic Ray Physics Program at the University of Utah, joins Ira to talk about cosmic rays, how they’re detected, and the challenges of finding the origin of particles like Amaterasu.

Listen to the podcast here.

Second highest-energy cosmic ray ever

November 21, 2023

second highest-energy cosmic ray ever

 

In 1991, the University of Utah Fly’s Eye experiment detected the highest-energy cosmic ray ever observed. Later dubbed the Oh-My-God particle, the cosmic ray’s energy shocked astrophysicists. Nothing in our galaxy had the power to produce it, and the particle had more energy than was theoretically possible for cosmic rays traveling to Earth from other galaxies. Simply put, the particle should not exist.

John N. Matthews standing beside large telescope mirrors at the Telescope Array Project's florescence detector station. Credit: Joe Bauman. Banner Photo Aboe: Artist’s illustration of the extremely energetic cosmic ray observed by a surface detector array of the Telescope Array experiment, named “Amaterasu particle.” OSAKA METROPOLITAN UNIVERSITY/L-INSIGHT, KYOTO UNIVERSITY/RYUUNOSUKE TAKESHIGE

The Telescope Array has since observed more than 30 ultra-high-energy cosmic rays, though none approaching the Oh-My-God-level energy. No observations have yet revealed their origin or how they are able to travel to the Earth.

On May 27, 2021, the Telescope Array experiment detected the second-highest extreme-energy cosmic ray. At 2.4 x 1020eV, the energy of this single subatomic particle is equivalent to dropping a brick on your toe from waist height. Led by the University of Utah (the U) and the University of Tokyo, the Telescope Array consists of 507 surface detector stations arranged in a square grid that covers 700 km2 (~270 miles2) outside of Delta, Utah in the state’s West Desert. The event triggered 23 detectors at the north-west region of the Telescope Array, splashing across 48 km2 (18.5 mi2). Its arrival direction appeared to be from the Local Void, an empty area of space bordering the Milky Way galaxy.

“The particles are so high energy, they shouldn’t be affected by galactic and extra-galactic magnetic fields. You should be able to point to where they come from in the sky,” said John Matthews, Telescope Array co-spokesperson at the U and co-author of the study. “But in the case of the Oh-My-God particle and this new particle, you trace its trajectory to its source and there’s nothing high energy enough to have produced it. That’s the mystery of this — what the heck is going on?”

Watch the video below and read the full article by Lisa Potter in @TheU.

Read additional articles about this story at the following. The Mirror (UK); LBC (UK); USA Today; CNN; India Times; Business Insider.

 

1st detection of heavy element from star merger

October 25, 2023

first detection of heavy element from star merger

 

“We only know of a handful of kilonovas with any certainty, and this is only the second one for which we have such detailed spectral information” said Tanmoy Laskar, assistant professor at the University of Utah, of the first detection of we have of heavy element from a star merger.

Tanmoy Laskar. Banner photo (above): This image from Webb’s NIRCam (Near-Infrared Camera) instrument highlights GRB 230307A’s kilonova and its former home galaxy among their local environment of other galaxies and foreground stars. The neutron stars were kicked out of their home galaxy and traveled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later. CREDIT: NASA, ESA, CSA, STSCI, ANDREW LEVAN (IMAPP, WARW)

Tanmoy Laskar and colleagues has used multiple space and ground-based telescopes, including NASA’s James Webb Space Telescope, NASA’s Fermi Gamma-ray Space Telescope, and NASA’s Neil Gehrels Swift Observatory, to observe an exceptionally bright gamma-ray burst, GRB 230307A, and identify the neutron star merger that generated an explosion that created the burst. Webb also helped scientists detect the chemical element tellurium in the explosion’s aftermath.

“Just over 150 years since Dmitri Mendeleev wrote down the periodic table of elements, we are now finally in the position to start filling in those last blanks of understanding where everything was made, thanks to Webb,” said Andrew Levan of Radboud University in the Netherlands and the University of Warwick in the UK, lead author of the study.

While neutron star mergers have long been theorized as being the ideal “pressure cookers” to create some of the rarer elements substantially heavier than iron, astronomers have previously encountered a few obstacles in obtaining solid evidence.

Kilonovas are extremely rare, making it difficult to observe these events. Short gamma-ray bursts (GRBs), traditionally thought to be those that last less than two seconds, can be byproducts of these infrequent merger episodes. In contrast, long gamma-ray bursts may last several minutes and are usually associated with the explosive death of a massive star.

The case of GRB 230307A is particularly remarkable. First detected by NASA’s Fermi Gamma-ray Space Telescope in March, it is the second brightest GRB observed in over 50 years of observations, about 1,000 times brighter than a typical gamma-ray burst that Fermi observes. It also lasted for 200 seconds, placing it firmly in the category of long duration gamma-ray bursts, despite its different origin.

“This burst is way into the long category. It’s not near the border. But it seems to be coming from a merging neutron star,” added Eric Burns, a co-author of the paper and member of the Fermi team at Louisiana State University.

Read the full article by Lisa Potter in @TheU.  Adapted from NASA Webb Space Telescope.

Retroviral Symposium

October 10, 2023

Developing HIV Anti-virals

The annual Retroviral Symposium held at Snowbird convened a wide-variety of scientists from many disciplines ... along with troupe of actors, a playwright and a dramaturge.

October 10, 2023

Infectious viral cores in the nuclei of infected cells are largely intact and uncoat near their integration sites just before integration. Illustration: The Animation Lab.

In September of 2023 the Department of Physics and Astronomy hosted the 12th International Retroviral Symposium at Snowbird Utah. The retroviral symposium is held bi-annually and is hosted alternatively in US or Europe. This symposium originally initiated from a group of NIH researchers which had strong collaborations with European scientists beginning in 1990’s.  

Fundamental mechanisms that ensure proper assembly, maturation and uncoating of retroviruses remain unclear. Understanding these mechanisms is critical for development of effective antivirals. While HIV antivirals now exists, the rapid evolution of HIV under antiviral selection requires new targets. The 12th Retroviral Symposium was focused on Assembly, Maturation and Uncoating and highlight fundamental biochemical, virological and biophysical mechanisms involved in these processes.

In a novel turn, this year’s symposium also featured a staged reading of an original play, “Emergence” by playwright Gretchen A. Case, professor at the U’s Department of Theatre and Associate Professor in the Division of Medical Ethics and Humanities at the U’s School of Medicine. Set “in the future, but not so far that it is unrecognizable,” the one-act has four characters: three scientists and an “AI,” as in artificial intelligence. The cast includes “Liv” who is saving her reproductive eggs in jars in a futuristic world where retroviral therapy in human reproduction is the norm. (Retroviruses, it turns out, are critical to the formation of the placenta.) The script is based on the book Discovering Retroviruses by Anna Marie Skalka, professor emerita at Fox Chase Cancer Center in Philadelphia. Skalka attended the symposium in a post-play discussion. 

 

 

Taking the leap

Also on-hand during the post-play discussion was Sydney Cheek-O’Donnell, chair of the U’s theater department, a long-time collaborator with symposium organizer and U professor of physics Saveez  Saffarian. Cheek-O’Donnell said that the project is an on-going attempt to understand and develop a way to work across multiple disciplines between science and arts /  humanities “so that others can take the leap… . Stories,” she says, “are one of the best ways to teach people complicated new ideas.” The Play was partially supported by a 1U4U award to Professors Case, Cheek-O’Donnell and Saffarian.

 

By David Pace

You can watch a video of the staged reading of “Emergence” below.

 

Ring-of-fire eclipse: How to see it

October 6, 2023

Ring of Fire Eclipse

 

“It’s like when you make a circle with your fingers and close one
eye. When you move your hand closer to your face, the circle gets bigger. Move it away, and it appears smaller.”

Paul RIcketts. Credit: Sara Tabin/Park Record

This is what Paul Ricketts has to say about the upcoming eclipse on Saturday October 14. “This will be a cool event. You’ll still see the surroundings get darker, you’ll feel it get colder, but you won’t be able to look at the eclipse without protective glasses,” continued  Ricketts, the director of the University of Utah’s South Physics Observatory. “Plus, this will last way longer than the total eclipse.”

This is a front row seat for Utahns to an annular eclipse the morning of the 14th. The so-called ring-of-fire eclipse is different than the total eclipse of 2017 but will still be spectacular.

A solar eclipse occurs when the moon’s orbit moves between the sun and the earth so that it blocks out the sun’s light and casts a shadow on Earth’s surface. During an annular eclipse, the moon is at a farther distance from the Earth. The distance makes the moon appear smaller, and it fails to block out the entire sun. The moon looks like a large black disk in front of the bright sun disk. This results in a ‘ring of fire’ around the moon’s silhouette.

Every year the moon drifts slowly farther away from the Earth—around one inch farther per year. Ricketts said that’s one reason to take advantage of these astronomical events while you can.

“Right now, our Earth position with the moon and the sun, they appear the same size in the sky, which is why we can enjoy total eclipses. A few billion years down the road, the moon will appear too small and we’d only get these types of annular eclipses.” Ricketts said. “We’re lucky to be alive right now. In the future, we’d only able to see annular eclipses that look like a much smaller black dot crossing the sun’s surface.”

While many will enjoy viewing the solar spectacle, the event is sacred to local Indigenous tribes. For some Indigenous tribes, an eclipse is a time of renewal and reflection through cultural practices that include fasting and meditation. Diné (Navajo) and Ute Indian Tribes do not watch, or even look at images of the eclipse. When posting images on social media, be mindful of people who want to avoid such images. Consider using a filter so your followers can opt-in to view any multimedia of the eclipse.

 

Learn how to see the eclipse by reading the rest of the story by Lisa Potter in @TheU.

outstanding contribution to cosmology

September 14, 2023

Cocconi Prize, outstanding contribution to cosmology

 

Kyle Dawson (right) and eBOSS co-leadership accept the Giuseppe and Vanna Cocconi Prize. CREDIT: COURTESY OF THE EUROPEAN PHYSICAL SOCIETY

The High Energy and Particle Physics Division of the European Physical Society (EPS) held its award ceremony at their annual conference on August 21, 2023, where they honored the field’s most influential research projects. The SDSS/BOSS/eBOSS collaboration won the Giuseppe and Vanna Cocconi Prize for an outstanding contribution to particle astrophysics and cosmology in the last fifteen years. The University of Utah was a key contributor to the BOSS and eBOSS collaborations.

“I joined the BOSS experiment when moving to the University of Utah. At the time, it felt like a gamble moving into a new cosmology experiment when starting as an assistant professor. It was clearly the right gamble to make as the experience has defined my career and has set me up to help plan large cosmology experiments over the next decade and beyond,” said Kyle Dawson, principal investigator of eBOSS and professor in physics and astronomy at the U.

The SDSS/BOSS/eBOSS projects are international collaborations involving hundreds of scientists that have fundamentally changed our understanding of the universe.

Read the full story in @TheU.

Why Scientists Haven’t Solved the Mystery of the OMG Particle

September 5, 2023

Solving The Mystery Of The 'OMG Particle'

 

Below the snow-covered peaks of the Andes Mountains, among scattered rocks and the scrub of prairie bushes, there sits at this very moment a 12-ton polyethylene tank holding 3,000 gallons of pure water.

 

All around it, spread out in every direction over an area nearly the size of Rhode Island, are 1,599 more such tanks, each identical to the first. These lonely sentinels have their eyes on the sky, patiently observing what human eyes cannot in the hopes of solving a mystery that began on another continent and more than three decades prior — a mystery that started with the Oh-My-God event.

It was the night of October 15, 1991. The University of Utah had set up an experimental observatory called the Fly's Eye in the isolation of Dugway Proving Ground, a sprawling 800,000-acre tract of land used by the U.S. Army to test biological and chemical weapons since the 1940s. On that night the Fly's Eye detected something called an air shower, a miles-long explosion of streaming particles invisible to the human eye and caused by high-energy interactions in the upper atmosphere. Each of the telescope’s detectors were designed to point at a different part of the field of view, in a similar way to insects’ compound eyes. It was this that earned the telescope its name. “We were hoping we might pick up something really unusual,” says David Kieda at the University of Utah, who worked on the telescope at the time. (Read more about the Fly's Eye Array here.)

Scientists looked at the data they'd collected and worked backward to deduce the properties of the space-borne particle that led to the air shower. The results weren't just shocking — they were thought to be impossible. They called their discovery the Oh-My-God particle.

While the Oh-My-God particle still remains the most energetic cosmic ray ever detected, a handful of others in the off-the-scales range have been observed in the years since, confirming that it wasn't a miscalculation or instrumentation failure, but in fact a real event. This is why 1,600 giant water-filled tanks have been installed in a grid formation across 3,000 square kilometers of the arid Mendoza region of Argentina. These are the specialized detectors of the Pierre Auger Observatory, forming an array designed to capture evidence of other extremely high-energy cosmic rays. "The quest for identifying the sources of the most energetic particles in the Universe continues," says Carsten Rott, chair of the Department of Physics & Astronomy at the U. "[But] not only at the Auger detector in Argentina, but also right here in Utah with the Telescope Array experiment."

 

Read the full story by DAVID ROSSIAKY in Slash Gear.

Gravitational Waves

August 16, 2023

Gravitational waves thrum through the cosmos

Last June dozens of astronomy enthusiasts gathered on the University of Utah campus to watch a live stream of a mysterious announcement. For weeks prior, scientists on Twitter, TikTok and IRL were abuzz with anticipation, awaiting results from the North American Nanohertz Observatory for Gravitational Waves’ (NANOGrav) 15 years’ worth of data.

 

NANOGrav confirmed what had long been suspected—gravitational waves are thrumming throughout the universe, emitting a low-pitched symphony that distorts the fabric of space and time.

 Tanmoy Laskar, assistant professor at the U’s Department of Physics & Astronomy thought of organizing the watch party to share in the excitement and discuss the results with the U community. He spoke with @TheU to explain the announcement.

Why is the astrophysics community so excited about the announcement?

This is very exciting because our current astrophysics and cosmology theories tell us that the universe should be full of these gravitational waves and, with these new results, the evidence for the existence of such a gravitational wave background just got much, much stronger. Furthermore, multiple global teams published their own, independent data sets on the same day and each team finds strong evidence for the presence of this gravitational wave background, which means that this signal is very likely real.

An amphitheater with dozens of people face towards a pull-down screen with the NSF and NANOGrav logo on it.

PHOTO CREDIT: TANMOY LASKAR

A live stream watch party for the NANOGrav announcement at the U.

 DOWNLOAD FULL-RES IMAGE

How did the collaboration detect the gravitational waves?


Gravitational waves are essentially a small stretch and squeeze in space and time. This means that if we want to detect a gravitational wave going by, we need to measure small perturbations to the distance between free-floating masses or to the time difference between two freely falling clocks. But the gravitational wave background that was the focus of the new studies involves waves with extremely long wavelengths—dozens of light years. This means to detect them we need clocks or masses separated by similar distances.

To navigate this, NANOGrav and their sister experiments used a technique called pulsar timing. Pulsars are rapidly spinning, very dense stars packing the mass of our sun into the size of a small city. They were discovered in 1967 by Dame Jocelyn Bell-Burnell as extraterrestrial objects producing regular radio pulses. The radio pulses from pulsars tend to be extremely regular because they behave similar to lighthouses. If you look at a lighthouse from the shore, its rotating beam of light flashes towards you at regular intervals. In the same way, pulsars appear as regular radio pulses seen when their lighthouse-like radio beams periodically sweep past Earth.

Astronomers realized that an array of pulsars spread across our galaxy could be used as a network of clocks. By timing the arrival of the pulses from these pulsars, one could look out for passing gravitational waves that would disrupt the timing of radio pulses that would usually arrive like clockwork. Tracking a large number of pulsars for disruptions is much more reliable. The idea is that if a gravitational wave goes through, then not only will there will be offsets in the time of arrival of the pulses from each pulsar from their expected times, such effects will be correlated in a predictable fashion between different pulsars depending on each pulsar’s direction and distance from Earth.

Of course a lot of different effects still need to be accounted for, including the motion of the Earth and planets in the Solar System and the slowing down of each pulsar as it slowly loses energy. Not to mention the fact that these gravitational waves have wavelengths that correspond to several Earth years, meaning that the observations need to be collected for over a decade to make a discovery!

To read the full interview with Lisa Potter visit @TheU. 

Carsten Rott, New Chair of Physics & Astronomy

July 20, 2023

Carsten Rott, New Chair of Physics & Astronomy

 

Professor Carsten Rott has been selected as new chair of the Department of Physics & Astronomy. Rott holds the Jack W. Keuffel Memorial Chair in High Energy Astrophysics and will replace Christophe Boheme as department chair beginning August 1.

Rott’s research explores the Universe in a fundamentally new way, using high-energy neutrinos detected with the IceCube Neutrino Telescope. In particular he is interested in searching for signatures of new physics associated with the high-energy neutrinos we detect. He also searches for new phenomena with the JSNS2 experiment which aims to search for oscillations involving a sterile neutrino in the eV2 mass-splitting range. (A sterile neutrino is believed to interact only via gravity and not via any of the other fundamental interactions of the Standard Model.)

Rott currently focuses on constructing next-generation neutrino detectors to better understand the sources of the most energetic phenomena in the Universe and to probe physics at fundamentally new scales. His team constructs calibration systems for the IceCube Upgrade and develops solutions for a very large volume neutrino detector at the South Pole, building on the expertise of the pioneering cosmic ray experiments conducted by the University of Utah. He also seeks sustainable solutions to construct future experiments with minimal environmental impact.  He can also be found working at Hyper-Kamiokande, a neutrino observatory being constructed on the site of the Kamioka Observatory, near Kamioka, Japan, and he seeks for dark matter with COSINE experiment.

After studying physics as an undergraduate at the Universität Hannover, Rott went on to receive a Ph.D. from Purdue University for work on the Collider Detector at Fermilab (CDF). He has been a member of the IceCube Neutrino Telescope since the start of the construction of the detector in 2005.  As a postdoctoral researcher at Penn State University he performed detector calibration and verification efforts for IceCube. For this task he traveled multiple times to the Amundsen Scott South Pole Station. Later he moved to The Ohio State University as a senior fellow of the Center for Cosmology and AstroParticle Physics (CCAPP). In 2013 he became an assistant professor at Sungkyunkwan University in South Korea and was subsequently promoted to tenured associate Professor.

In 2021 Rott became a professor at the U where most recently he served as department director of graduate studies. He will hold the position of chair through December 2025.

Rott “is an exceptional educator and researcher, and has my complete confidence and support in his role as Chair,” remarked Peter Trapa, dean of the College of Science who made the announcement on June 28. “I look forward to working with Carsten to advance the department, particularly as it moves to its new home in the Crocker Science Complex in 2025.”

“I am grateful to Professor Christoph Boehme for his leadership over the past four years, first as Interim Chair, and then as Chair for the last three years.,” Trapa continued. “Christoph has made deep contributions to the department in advancing its research and educational missions during a time that was often consumed with the COVID-19 pandemic.” 

Boheme will serve as Special Advisor to the Chair for the period August 1, 2023 through June 30, 2024.

About the Department

New home for the Dept. of Physics & Astronomy

The U’s  Department of Physics & Astronomy is committed to pursuing key science questions within an inclusive academic community; to training and diversifying the next generation of researchers, educators, and technology workforce leaders; and to inspiring an appreciation for knowledge in students and the wider community.

In pursuit of this mission, the department supports the highest levels of research and teaching among its faculty members. We strive to enable the success of undergraduate and graduate students by creating an academically excellent, efficient, and comfortable learning environment. Our goal is that organizations and individuals in the local and global community will benefit from our research and accomplishments.

The Department of Physics & Astronomy will be relocating from the James Fletcher Building to the new Applied Science Project as part of the Crocker Science Complex. The department will offer classes in its new home in Spring Semester, 2025.

Sky Survey Data Releases 2 Million Stellar Objects

June 26, 2023

The universe is big, and it’s getting bigger.

To study dark energy, the mysterious force behind the accelerating expansion of our universe, scientists are using the Dark Energy Spectroscopic Instrument (DESI) to map nearly 40 million galaxies, quasars and stars. Today, the collaboration publicly released its first batch of data, with nearly 2 million objects for researchers to explore.

The 80-terabyte data set comes from 2,480 exposures taken over six months during the experiment’s “survey validation” phase in 2020 and 2021. Between turning the instrument on and beginning the official science run, researchers made sure their plan for using the telescope would meet their science goals—for example, by checking how long it took to observe galaxies of different brightness, and by validating the selection of stars and galaxies to observe.

“The fact that DESI works so well, and that the amount of science-grade data it took during survey validation is comparable to previous completed sky surveys, is a monumental achievement,” said Nathalie Palanque-Delabrouille, co-spokesperson for DESI and a scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), which manages the experiment. “This milestone shows that DESI is a unique spectroscopic factory whose data will not only allow the study of dark energy but will also be coveted by the whole scientific community to address other topics, such as dark matter, gravitational lensing and galactic morphology.”

Kyle Dawson

DESI uses 5,000 robotic positioners to move optical fibers that capture light from objects millions or billions of light-years away. It is the most powerful multi-object survey spectrograph in the world, able to measure light from more than 100,000 galaxies in one night. That light tells researchers how far away an object is, building a 3-D cosmic map.

“This new sample represents the first science-quality data taken with this powerful new instrument. These survey-validation data are better quality and provide spectra and classification of a wider range of stars, galaxies and quasars than the data we expect in the main five-year program,” said Professor Kyle Dawson. Dawson of the University of Utah was one of the two primary leads of the survey validation effort and is also DESI co-spokesperson.  “We have learned from these data how to build the most effective cosmology program.”

Read the entire article in @TheU.