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Department of Physics & Astronomy at the University of Utah

A Hotspot for Powerful Cosmic Rays

Physicists a Step Closer to Finding Mysterious Sources

July 8, 2014 – An observatory run by the University of Utah found a “hotspot” beneath the Big Dipper emitting a disproportionate number of the highest-energy cosmic rays. The discovery moves physics another step toward identifying the mysterious sources of the most energetic particles in the universe.

University of Utah physicists Gordon Thomson, Charlie Jui and John Matthews discuss the Telescope Array cosmic ray observatory’s discovery of a “hotspot” – located beneath the Big Dipper in the northern sky – emitting an unusual number of ultrahigh-energy cosmic rays. The source of these rays, which are the most energetic particles in the universe, remains unknown, but the new finding will help narrow the search. Photo Credit: Lee J. Siegel, University of Utah

“This puts us closer to finding out the sources – but no cigar yet,” says University of Utah physicist Gordon Thomson, spokesman and co-principal investigator for the $25 million Telescope Array cosmic ray observatory west of Delta, Utah. It is the Northern Hemisphere’s largest cosmic ray detector.

“All we see is a blob in the sky, and inside this blob there is all sorts of stuff – various types of objects – that could be the source” of the powerful cosmic rays, he adds. “Now we know where to look.”

A new study identifying a hotspot in the northern sky for ultrahigh-energy cosmic rays has been accepted for publication by Astrophysical Journal Letters.

Thomson says many astrophysicists suspect ultrahigh-energy cosmic rays are generated by active galactic nuclei, or AGNs, in which material is sucked into a supermassive black hole at the center of galaxy, while other material is spewed away in a beam-like jet known as a blazar. Another popular possibility is that the highest-energy cosmic rays come from some supernovas (exploding stars) that emit gamma rays bursts.

Lower-energy cosmic rays come from the sun, other stars and exploding stars, but the source or sources of the most energetic cosmic rays has been a decades-long mystery.

The study was conducted by 125 researchers in the Telescope Array project, including Thomson and 31 other University of Utah physicists, plus 94 other scientists from the University of Tokyo and 28 other research institutions in Japan, the United States, South Korea, Russia and Belgium.

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Bryce Canyon Astronomy Festival

From the Bryce Canyon National Park Website

2014 Bryce Canyon Astronomy Festival: Star Stories from Down Under

Join us for our 14th Annual Astronomy Festival (June 25 - 28, 2014) where Bryce Canyon's Dark Rangers and the Salt Lake Astronomical Society welcome Australia's award-winning photographer and amateur astronomer Alex Cherney. Don't miss this keynote presentation on Friday, June 27 at 9:15 pm -- Alex's debut appearance in the United States. See his stunning photography from the wilds of Australia and New Zealand -- two of the few places on Earth with even darker night skies than Bryce Canyon. In the Australian Outback the Milky Way is so bright that many of the native people's constellations were not made in connect-the-dots fashion from star-patterns, but from the 3-dimensional dark clouds (stellar cocoons) within the Milky Way.

If you've ever dreamed of going on an Australian night-sky "walk-about," here's your chance to follow in the footsteps of an expert. Listen to Alex tell of these 20,000-year-old sky stories, and his own adventures in the wilds of Australia, beneath the backdrop of his stunning night sky videography set to moving music. In the meantime, enjoy some samples of his talent here.

Visit the Bryce Canyon National Park Website for schedules, directions and more information.


Helping the Public Reach for the Stars

U Opens Astronomy Center June 11 for Star Parties & More

Paul Ricketts, Hrly Research Assistant, and part of the AstronomUrs outreach team, aligning the Meade 14" LX200 GPS telescope. Photo Credit: University of Utah

June 5, 2014 – The University of Utah has a new location for people who enjoy outer space. The Astronomy Outreach Center will begin operating at 7 p.m. Wednesday, June 11 with an open house, a brief lecture and a party to observe the sun and stars.

The university’s Department of Physics and Astronomy has held star parties for years on the roof of the South Physics Building. The new space— located in room 408 below the rooftop observatory— finally provides a permanent, roughly 30-seat gathering place for astronomy presentations and demonstrations for the public, K-12 students, scouting and community groups and private and public star parties.

“In the past, when a school group would want to come to us and have a presentation or activity, we would have to search around for a classroom not in use at a given time. This often wouldn’t work,” says astronomer Tabitha Buehler, coordinator of the new center and head of a university astronomy outreach group known as the AstronomUrs.

“Now we have a space that is dedicated to public outreach, so we can accommodate more groups,” says Buehler, who is also an assistant professor-lecturer in physics and astronomy. “One responsibility of the university is to reach out to people and educate them about the different exciting things up here.”

The idea for the Astronomy Outreach Center began when former physics and astronomy chair Dave Kieda, now dean of the U’s Graduate School, and Harold Simpson, the department’s facilities director, were devising new ways to improve the department and get it more involved with the community, Buehler says.

The center also will be the base for remote-controlled operations of the university’s Willard L. Eccles Observatory at the 9,600-foot level on Frisco Peak in southern Utah.

The June 11 opening will feature public use of solar telescopes at 7 p.m., a brief presentation about the sun at 8:40 p.m. followed by a public star party.

Free parking will be available after 6 p.m. in the two parking lots east of the South Physics Building. More details and a map are located here.

To request and schedule a public astronomy event – either at the Astronomy Outreach Center or off-campus – schools, community organizations and other groups should email the center at:

Download the Public Open House Poster

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Watching HIV Bud from Cells

Study Shows Last-Minute Role of Protein Named ALIX

University of Utah physics doctoral student Pei-I Ku prepares a sample for the digital microscope she uses to make movies and photographs of the AIDS-causing human immunodeficiency virus budding from human cells in the laboratory. The microscope is in a glass chamber to keep the cells at body temperature so researchers can watch the process over time. Ku is the first author of a new study in which University of Utah researchers combined imaging technology and biochemistry to make such images. The method revealed that a protein named ALIX gets involved in the process later than believed previously. Photo Credit: Tom Bear ( for the University of Uta

May 16, 2014 – University of Utah researchers devised a way to watch newly forming AIDS virus particles emerging or “budding” from infected human cells without interfering with the process. The method shows a protein named ALIX gets involved during the final stages of virus replication, not earlier, as was believed previously.

“We watch one cell at a time” and use a digital camera and special microscope to make movies and photos of the budding process, says virologist Saveez Saffarian, an assistant professor of physics and astronomy and senior author of a new study of HIV budding published online today in the Public Library of Science journal PLOS ONE.

“We saw ALIX recruited into HIV budding for the first time,” he says. “Everybody knew ALIX is involved in HIV budding, but nobody could visualize the recruitment of ALIX into the process.”

The finding is “fundamental basic science” and has no immediate clinical significance for AIDS patients because ALIX is involved in too many critical functions like cell division to be a likely target for new medications, Saffarian says.

“We know a lot about the proteins that help HIV get out of the cell, but we do not know how they come together to help the virus get out, and it will be in the next 10 to 20 years that we will know a lot more of about this mechanism,” he adds. “Would this be a drug target? Would this be a part of biochemistry used in a therapeutic or biotech industry later on? I can’t tell you now. But if it was not because of our curiosity as a species, we would not have the technology we have today.”

The new study “is nice work,” says HIV budding expert Wes Sundquist, who advised Saffarian and is professor and co-chair of biochemistry at the University of Utah School of Medicine. “It’s of genuine interest for those of us who study the mechanism of HIV assembly.”

The study was funded by the National Science Foundation. Saffarian conducted the study with first author, Pei-I Ku, a University of Utah doctoral student in physics; Mourad Bendjennat, a postdoctoral research associate in physics and astronomy; technician Jeff Ballew; and Michael Landesman, another postdoctoral fellow in physics and astronomy who previously worked in Sundquist’s biochemistry lab.

Full Press Release.


Nearest Bright ‘Hypervelocity Star’ Found

Speeding at 1 Million mph, It Probes Black Hole and Dark Matter

An astrophysicist-artist's conception of a hypervelocity star speeding away from the visible part of a spiral galaxy like our Milky Way and into the invisible halo of mysterious "dark matter" that surrounds the galaxy's visible portions. University of Utah researcher Zheng Zheng and colleagues in the U.S. and China discovered the closest bright hypervelocity star yet found. Photo Credit: Ben Bromley, University of Utah

May 7, 2014 – A University of Utah-led team discovered a “hypervelocity star” that is the closest, second-brightest and among the largest of 20 found so far. Speeding at more than 1 million mph, the star may provide clues about the supermassive black hole at the center of our Milky Way and the halo of mysterious “dark matter” surrounding the galaxy, astronomers say.

“The hypervelocity star tells us a lot about our galaxy – especially its center and the dark matter halo,” says Zheng Zheng, an assistant professor of physics and astronomy and lead author of the study published recently in Astrophysical Journal Letters by a team of U.S. and Chinese astronomers.

“We can’t see the dark matter halo, but its gravity acts on the star,” Zheng says. “We gain insight from the star’s trajectory and velocity, which are affected by gravity from different parts of our galaxy.”

In the past decade, astronomers have found about 20 of these odd stars. Hypervelocity stars appear to be remaining pairs of binary stars that once orbited each other and got too close to the supermassive black hole at the galaxy’s center. Intense gravity from the black hole – which has the mass of 4 million stars like our sun – captures one star so it orbits the hole closely, and slingshots the other on a trajectory headed beyond the galaxy.

Zheng Zheng, an assistant professor of physics and astronomy at the University of Utah, led a team of American and Chinese scientists who discovered the closest bright hypervelocity star of 20 yet found. Scientists believe each hypervelocity star began as part of a binary pair of stars near the center of our Milky Way galaxy, where extreme gravity from a supermassive black hole sucked in one star in the pair and, like a bolo, simultaneously hurled the other star -- a new hypervelocity star -- toward the edge of the galaxy. Photo Credit: Lee J. Siegel, University of Utah

Zheng and his colleagues discovered the new hypervelocity star while conducting other research into stars with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, or LAMOST, located at the Xinglong Observing Station of the National Astronomical Observatories of China, about 110 miles northeast of Beijing.

LAMOST boasts a 13.1-foot-wide aperture and houses 4,000 optical fibers, which capture “spectra” or light-wavelength readings from as many as 4,000 stars at once. A star’s spectrum reveals information about its velocity, temperature, luminosity and size.

LAMOST’s main purpose is to study the distribution of stars in the Milky Way, and thus the galaxy’s structure. The new hypervelocity star – named LAMOST-HVS1 – stood out because its speed is almost three times the usual star’s 500,000-mph pace through space: 1.4 million mph relative to our solar system. Its speed is about 1.1 million mph relative to the speed of the center of the Milky Way.

Despite being the closest hypervelocity star, it nonetheless is 249 quadrillion miles from Earth. (In U.S. usage, a quadrillion is 1,000,000,000,000,000 miles or 10 to the 15th power, or 1 million billion).

“If you’re looking at a herd of cows, and one starts going 60 mph, that’s telling you something important,” says Ben Bromley, a University of Utah physics and astronomy professor who was not involved with Zheng’s study. “You may not know at first what that is. But for hypervelocity stars, one of their mysteries is where they come from – and the massive black hole in our galaxy is implicated.”

Full Press Release


Astronomy Week

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Monday, May 5:
Telescopes in the Park, Solar Observing at Liberty Park,
Noon - 4:00 pm

Join the University of Utah's AstronomUr Outreach Group at Liberty Park to view the Sun through specialized telescopes! Learn more...

Tuesday, May 6:
Sidewalk Solar Observing Party, Downtown City Library
Noon - 4:00 pm

Think star-gazing is only possible at night? Think again! Join us at the City Library in downtown Salt Lake for solar observing. Learn more...

Wednesday, May 7:
Star Party & Solar Observing at the South Physics Observatory 
6:00 pm - 11:00 pm

Let our observatory guides take you on a tour of the night sky! Learn more...

Thursday, May 8:
Film Festival with Topical Discussions, 408 South Physics Building, University of Utah
6:00 pm - 8:00 pm

Join our AstronomUrs in a cosmic journey Hollywood-style and learn why space is so hard to replicate on the big screen! Learn more...

Friday, May 9:
Star Party at the South Physics Observatory, University of Utah
8:00 pm - Midnight

Come explore astronomy through one of our 14 telescopes and learn how astronomers make discoveries! Learn more...

Saturday, May 10:
Astronomy Activities at the Natural History Museum of Utah,
Noon - 4:00 pm

Learn more about telescopes and how astronomers make discoveries with a variety of presentations and activities! Learn more...


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