The hunt for the origins of the universe’s most energetic particles

The hunt for the origins of the universe's most energetic particles


Dec 10, 2024

The University of Utah’s Cosmic Ray Research program, along with partner institutions in the Telescope Array collaboration is looking to crack the case of exactly what the mysterious particles are that carry far more energy than an Earth-bound accelerator can deliver.

The researchers’ recent observation of the second-highest energy cosmic ray on record is providing important clues.

At a seminar on campus September 26, Jihyun Kim, senior research associate in the Department of Physics & Astronomy, presented the Cosmic Ray Research team’s findings from the Telescope Array, an international experiment based in the high desert of western Utah, where 850 detectors are arranged across half a million acres of public land, with 250 more on the way.

“We are hosting the experiment here in Utah,” Kim said. “We design, maintain, and operate everything. We go down with our students, and they learn how to operate all the systems, collect the data and analyze it by themselves. This is a really unique research experience [for our students].”

She shared the latest research and insights pertaining to cosmic rays, utilizing the largest cosmic ray observatory in the Northern Hemisphere. The research group’s mission is to achieve breakthroughs in the field of particle astrophysics. Funded by the National Science Foundation, the Cosmic Ray Research program is particularly interested in the properties of ultra-high energy cosmic rays, or UHECRs.

Read the full article by Ethan Hood in @TheU.

 Taking it to the Startup Slopes

Taking it to the startup slopes


Above: Thomas Tang

Thomas Wei-Tsu Tang, BS’94 in physics, is an extraordinary competitor.  A two-time Olympian in alpine skiing (Calgary, 1988 and Albertville, 1992), he has also competed in a World Cup and a World Championship in skiing.

 

“I am proud to be an Olympian,” says Tang. “Elite competition pushes the limits of humanity, our physical and mental capacity, our emotions and compassion for each other.” For Tang, pushing those limits has extended from the slopes to business, to family and, finally, to something else that makes this U alumnus extraordinary, his capacity to pay it forward.

Tang is the founder and president of Apantac LLC, a global leader in design and development of high-quality, cost-effective image signal processing equipment. The company will be celebrating its 17th anniversary in 2025.

“The Apantac product line, which now includes more than 200 items, has been designed to provide the broadcast and professional audio-video industry with flexible and innovative technology solutions for video processing and signal extensions and switching,” says Tang.

Apantac clients include TV stations, news studios and sports broadcasters like ESPN and Fox Sports. “The KSL-TV broadcast house in downtown Salt Lake is a wonderful local customer, they used our equipment to broadcast the 2024 Paris Olympics,” says Tang. “Also, large social media companies like Google, Meta, and Amazon use our products for their worldwide global event centers.”

Prior to founding Apantac, Tang was the director of marketing for Philips Broadcast in West Valley City.  After Philips divested, he decided to help a small startup company in Redmond, Washington and oversaw sales and marketing as well as strategic planning and product development. While there, from 2004 to 2008, Tang grew the business more than eightfold.

"At this small startup with very limited resources, I was working so hard, one day my wife said to me, ‘If you’re going to work this hard, you should work for yourself!’ This put the idea in my head that I should start my own company. I knew that I wanted to make products for the video industry, so I quit my job in early 2008 and started working on how to realize these ideas,” says Tang.

“During the first three years, times were tough,” says Tang. “And when things were not going well, I dug into being an Olympian. When you train, you know the pain is transitory, and you know you’re getting stronger and something better is coming! Athletes understand they’re not always going to have a good day, but hard work and persistence pay off.”

By the end of 2008, he had begun developing products in his basement. In April 2009, the company’s first product, a Multiviewer, was launched. The device allowed one user to view multiple video sources on a single screen or across multiple screens. It received the prestigious Pick Hit Award at the National Association of Broadcasters conference. The award is given to products that demonstrate outstanding technology and innovation not previously showcased at the event.

Since then, Apantac has grown significantly, offering more than 200 products and shipping to more than 40 countries. Tang and his team had been involved in numerous broadcast and professional audio-visual projects worldwide.  Apantac’s customers include national broadcasters, Soccer World Cups, Olympic games and more.  “We now ship from pole to pole, from Greenland to New Zealand,” says Tang. Apantac has offices in the U.S., Europe, Latin America and Asia.

From Taipai to Salt Lake

Tang’s story of determination and persistence started in Taipei, Taiwan, where he was born in 1964. “I was the youngest, and the only son in a Taiwanese family, so the pressure for me to succeed was extremely high,” he says.

Tang attended a strict private school, Tsai Hsin, that started in kindergarten. He always loved sports, but he struggled academically. “My grades were always below average,” says Tang.  “I did not perform well in the traditional Taiwanese academic system. I was not really allowed to play sports, because the teachers in my school would punish me for not doing well academically. I was stuck in a rut and my parents realized that and decided it was best to move to the United States for a change of environment.”

Tang’s father, Mei-Chun Tang, was educated in the U.S. at Berkeley and at Columbia. At the time, he was a professor of anthropology at National Taiwan University and there was an exchange professorship program between the University of Utah and National Taiwan University.

As part of the exchange program, the family moved from Taipai to Salt Lake City in September 1977, when Tang was 13 years old. He attended 8th grade at Bryant Junior High School and began learning English as a second language.

“In 1977, Salt Lake was a very safe and small town, there was nothing past 7200 South.  I used to hitchhike to get around town,” remembers Tang. “The transition was difficult. New people, new school, new language. But being a good athlete, I was accepted very quickly into the American culture,” says Tang.

He later attended East High School. “At that time, I really wanted to go to medical school but biology was difficult for me because English was my second language. However, I was always good at math, so physics was a natural fit when I started at the University of Utah,” says Tang.

Tang remembers many faculty members in physics, especially Own Johnson, George Williams, Fritz Luty, Dave Ailion and Eugene Loh.

While attending the U, he worked in the Marriott library shelving books and eventually landed an internship in the chemistry department for faculty members Jim Wang and Chuck Wight. “Chuck was a young professor in his 30s,” says Tang. “He was a great mentor and had the most impact on me. We even published a paper together, ‘Low Temperature Photochemistry in Amorphous Films,’ Proc. SPIE 1056.”

By 1989, Tang had essentially finished his bachelor’s degree in physics. When the chance presented itself, he accepted a role at Evans & Sutherland in the computer graphics division. “I remember Microsoft came to campus to recruit me, but working at Evans & Sutherland was the ultimate honor for a U of U student, so I accepted the job.”

“In fact, Evans & Sutherland was one of the largest tech companies in the valley, employing around 1,500 people.  The management encouraged us to transfer between different departments to expand our technical horizon. My first job was porting applications between UNIX workstations, Linux kernels, PC graphics card drivers and graphical user interfaces. I later worked on several exciting projects, including the world’s first F-14, F-16, and other flight simulators.  That’s where I learned about the technology of video processing.” He stayed at Evans & Sutherland until 1997.

A sports family

Tang and his wife, Penny, met on campus in the Olpin Union building. In the 1990s, their student organization reserved a gym in the HPER Complex. “She was playing badminton, and I was playing basketball. After 10 o’clock, when the HPER building closed, a few of us decided to go to the Union to play pool. We shared a table, and the rest is history,” says Tang.

They were married in 1994 and now have three children: Emma, 23, is a recent graduate of NYU, getting ready to go to law school; Calcy, 20, is studying Kinesiology at the U; and Winston, 18, is ski racing in Europe. “All three of our kids are active in sports,” says Tang who explains that Emma was a professional figure skater who has competed internationally, and Calcy qualified for the Olympics and skied in the 2021 World Championship.

When Tang turns to his wife, his sentiment is one of respect and gratitude. “I’m extremely grateful for my wife, Penny. She encouraged me in those early years when things were tough. She came from an affluent family in Taiwan, and during our early years, she would joke about having never been ‘poor and lonely at the same time,’” remembers Tang. “Without her, I wouldn’t be where I am today.”

Bringing it full circle

While a proven competitor in sports, Tang’s more collaborative side comes to the fore with his siblings, Grace Hui Tang and Bonnie Y. Tang. The three of them have invested in a permanent named space in the main atrium of the Stewart Building, still under construction, in honor and memory of their parents, Dr. Mei-Chun Tang and Pi-Yung Chen.

A historic building, the Stewart, when its renovation is complete, will be physically joined with the new Applied Science Building and together will complete the Crocker Science Complex on Presidents Circle. A building dedication and opening ceremony is planned for July 2025.

 

ACCESS Scholar: Ella Bleak

ACCESS Scholar, Ella Bleak


November 18, 2024
Above: Ella Bleak

Ella Bleak’s journey as a self-proclaimed science nerd started at a young age.

Her inner nerd was fostered by high school chemistry and biology teachers, and having a professor in developmental biology with a PhD from the U as a neighbor didn’t hurt, either.  That led her to discover ACCESS Scholars, a College of Science first-year community, research and scholarship program for students in Science, Technology, Engineering and Mathematics (STEM) disciplines.

“I didn’t really have many expectations,” explained Ella. “I didn’t know very much about the program when I got into it, other than the research aspect. It ultimately was one of the main reasons I decided to come to the U because I was looking for early research opportunities. What I was not expecting was the lasting effects it had on my experience at the U.”

Through ACCESS, Ella was placed in the Karasov lab. Led by School of Biological Sciences Assistant Professor Talia Karasov, they work to study tailocins, phage-tail-like bacteriocins used by bacteria to compete with other bacteria for resources and space—essentially weapons used in a bacteria warfare. More specifically, they’re characterizing the interactions between tailocins and their target bacteria’s lipopolysaccharide (structures on the bacterial membrane which tailocins can bind) to understand how tailocins differentiate between closely related strains.

Despite an initial hesitancy due to its lack of chemistry, Ella says it’s the best lab she could have ended up in. Publishing in the Karasov lab opened up the opportunity for Ella to become a Beckman Scholar, an institutional award funding research for scholar-faculty mentor pairs, allowing her to combine her two science loves and expand her research into a biochemistry focus.

“My lab has been one of the most amazing and supportive resources I have at the U, and I am so lucky to be in that lab because of ACCESS,” says Ella. “Beyond lab work, ACCESS helped me get involved in the campus early. I was more confident in applying to jobs, talking to professors, and getting involved with clubs. ACCESS really was the thing that catalyzed all of my college experiences.”

Some of those opportunities ACCESS Scholars opened up include becoming a UROP Scholar, Teaching Assistant, and Science Ambassador for the College of Science.

“The major benefit to ACCESS compared to other research options is the community and network that becomes available to you. If you are looking for ways to find friends or mentors in college then ACCESS is the way to do it.”

Upon graduating, she plans to get a PhD in chemical biology and end up in research.

“I don’t yet know if that means academia, industry, or some other area, but I have found a love for research and know that I want to be doing it for the rest of my career.”

By Seth Harper

Exploring the Cosmic Unknown

Exploring the cosmic unknown with the Dark Energy Spectroscopic Instrument


Nov 12, 2024
Above: TA view of DESI’s fully installed focal plane, which features 5,000 automated robotic positioners, each carrying a fiber-optic cable to gather galaxies’ light.

Although the Dark Energy Spectroscopic Instrument sounds like something used at Hogwarts to practice wizardry, it is very much something based in real science.

The Dark Energy Spectroscopic Instrument is working its own magic to probe the fundamental physics that describe the universe and measure the effect of dark energy.

Kyle Dawson, University of Utah professor of physics and astronomy, is part of the Dark Energy Spectroscopic Instrument team and tells us more about this earth-bound, very complex instrument.

Listen to the full podcast posted in KPCW by Katie Mullaly and Lynn Ware Peek.

Navigating the Universe and Self

Navigating the Universe and Self


Oct 14, 2024
Above: Ethan M. Hood, a third-year honors student studying physics and astronomy.

By Ethan Hood

“I started out as a general studies student at Salt Lake Community College. I have a wide range of interests, and it was hard to pin down what I wanted to study.

That was until I took elementary astronomy and felt my passion for the subject shine through like Sirius. That led me down the path toward joining the Astronomical Society of the Pacific, where I volunteered as an Eclipse Ambassador. This astronomy-focused outreach program serves under-resourced communities that haven’t been exposed to science. Participating in that made me realize that I hope to inspire future astronomers, and to be a public-oriented science communicator like Carl Sagan.

While I’m here at the U, I aim to be more involved in the community. I want more than just a degree. I want to develop my social skills and build strong relationships. I want to feel like a person at the U, as opposed to just a college student. Our campus is meant to be a place for students to find community—and I want to do my part in ensuring that.

I’m grateful and incredibly fortunate to be a Presidential Intern.

Read the full article in @TheU.

Pete Johnson: An Abundant Source of Energy

Pete Johnson, An Abundant Source of Energy

 


October 8, 2024
Above: Pete Johnson. Credit: courtesy of Pete Johnson

Pete Johnson, BA’03 physics, is a source of boundless energy. At just 45, the husband and father of four has earned a master’s degree in mechanical engineering at Stanford, founded and built several leading companies, worked as a venture capitalist and investor in Silicon Valley, and is currently the president and CEO of Koloma, Inc., a global leader in geologic hydrogen exploration.

Left to right, Grace, Levi, Pete, Kristin, Josh and Sydney Johnson. Credit: courtesy of Pete Johnson

What focuses his energy, though, is his family — wife Kristin, daughter Sydney, 16; daughter Grace, 14; son Josh, 10; son Levi, 8.

Johnson is exploring and developing technologies to tap a new source of energy that is powerful, vast, and clean. It’s known as geologic hydrogen. Studies suggest that the earth produces significant amounts of hydrogen through natural geochemical processes and that it may be accumulating in formations below the surface. If sufficiently sized reservoirs can be found, geologic hydrogen could help fuel the U.S. economy for centuries to come while reducing emissions and carbon footprints.

Johnson grew up in The Avenues neighborhood of Salt Lake during the eighties. “I was born the fifth of six sons and had an unbelievably fun, Huck Finn-type of childhood exploring the foothills by foot and bike with my brothers,” he says. “We also spent a lot of time skiing, boating and going to high school sports games for my older brothers.”

At East High School, Pete was inspired by several teachers and classes, including AP Biology and AP Calculus. “I think the most inspiring person for me at East was Keeko Georgelas, the head coach who revitalized the school’s football program and took it from a perennial doormat to one of the top programs in the state. Keeko put into our heads that we could do great things.” Pete took those words to heart, channeling that motivation as he led the East High football team to a state championship in 1997, his senior year. It was the first championship at East since 1974.

Awarded a four-year presidential scholarship, Johnson enrolled at the University of Utah for Fall semester 1997 intending to be an environmental or civil engineering major. “I was interested in biology and math and wanted to be in the environmental remediation and hydrology world, in part thinking that it would give me lots of opportunities to work outside.”

Johnson completed the prerequisite courses before serving a two-year church mission. When he returned, in 2000, he struggled to find passion for the course work. He persisted and took a few more civil engineering classes but wasn’t intrigued with the subject matter.

“I started thinking about what else I could do and was in the middle of a general physics course taught by Sid Rudolph who was just a crazy man and unbelievably passionate about physics,” says Johnson. “I decided to give it a try and was pleasantly surprised with the curriculum and the way I was challenged by the science and the math.”

“I had tough, interesting courses in quantum physics, nuclear physics, electromagnetics and other areas from faculty [not only] Sid Rudolph, [but also] Clayton Williams, Mikhail Raikh and Rich Ingebretsen," says Johnson. "Rich was a longtime family friend who also taught me how to run rivers.” It was the cumulative effect of these courses, and perhaps hitting the rapids, that inspired Johnson to become an entrepreneur in the energy sector.

“My dad was in energy, and it was always something that I was interested in," says Johnson. "So, I applied to the mechanical engineering graduate programs at Stanford and MIT and was accepted into both programs."

Johnson chose Stanford and spent two years there, mostly doing biomechanical research where he found some fascinating topics in stem cell implantation into heart tissue. “At that point, it was time to propose a PhD project, but I struck out on two or three different ideas, being told by my advisor that these ideas sounded more like business plans than research projects. I kept trying to ‘science’-up the proposals but wasn’t getting it, and I realized, probably later than my advisor, that I was more interested in stepping out and pursuing things in Silicon Valley than I was in three-to-five more years in the lab. So, I finished with a master’s degree and never looked back.”

Modern day gold rush

The company name, Koloma, was inspired by the small town of Coloma, California, where gold ore was discovered in 1848 which led to the California Gold Rush that transformed the country and the entire economy. Johnson and company founders Tom Darrah, Paul Harraka and Scott McNally visited the site in 2021 to launch Koloma, Inc. Geologic hydrogen has also been referred to as gold hydrogen, so the team thought the name was appropriate. An appreciation for the history of exploration and the value of learning from the past is embedded in the company.

“The unique thing about Koloma is that we have 20 years of data advantage and a big head start in the field, and that data advantage has led to a large number of tools and techniques we can build and validate through our exploration work,” says Johnson.

Koloma has already developed the technology to identify the most promising regions for geologic hydrogen potential. The company continues to conduct geophysical studies and some preliminary drilling projects around the world. Johnson anticipates large-scale hydrogen production to begin by 2030 if they are successful in their exploration efforts.

As a new primary energy source, naturally occurring geologic hydrogen could be a powerful tool to help move towards lower carbon energy forms in the U.S. and around the world.

The Science

Geologic hydrogen is generated naturally in the Earth’s iron-rich mantel by an oxidation-reduction reaction known as serpentinization. Through this water-rock reaction, considerable quantities of hydrogen are continuously produced and stored in geological formations below the surface. In fact, geologic hydrogen can be produced with low-carbon intensity, resulting in a low-carbon footprint on par with electrolysis. In addition, the process does not require external water inputs or external energy inputs such as heat or electricity.

For these reasons, geologic hydrogen presents a highly efficient, low-cost and low-greenhouse-gas energy source.

Even with all that potential energy in development, Johnson’s internal energy source is rooted in Mountain View, California, near Stanford where he and his family reside.

“We’ve always got plenty going on,” says Johnson of his family which spends weekends at soccer games, hiking in the redwoods or hanging out on the Northern California coast.

He met his wife Kristin in September 2003, the first weekend he was in Palo Alto for graduate school. “Kristin had just taken a job with Pfizer in sales. I was smitten early on, but she was dating guys who didn’t have years of grad work in front of them and were already going places, so it took me about a year of building trust as a friend before she really started to see me as a viable option!”

“Once we started dating it was clear we had something great going on, and I think my mom would have killed me if I messed it up so I was careful,” says Johnson who proposed at sunrise on top of Half Dome in Yosemite National Park. They were married in October 2005 in Salt Lake City.

Pete Johnson’s advice to others is simple and, not surprisingly, family-centric: “Avoid thinking that being passionate about your work means you won’t be able to be a great spouse and parent. Find a way to make it all work.”

You can read a recent story in CNBC about Bill Gates and Jeff Bezos' backing Pete Johnson's Kolomo, Inc here.

APS Fellowship awarded to Tino Nyawelo

APS Fellowship awarded to Tino Nyawelo


October 4, 2024
Above: Tino Nyawelo

The American Physical Society has elected the Society's 2024 Fellows, one of whom is University of Utah's Tino Nyawelo. 

 

The APS Fellowship Program recognizes members who have made exceptional contributions in physics research, important applications of physics, significant contributions to physics education, or leadership in or service to APS.

This year,149 Fellows were selected and recognized for their contributions to science. Nyawelo's honor was by recommendation of the American Physical Society Forum on Diversity and Inclusion at its September council meeting. The citation reads that the award is being made “[f]or significant contributions to creating and sustaining physics and STEM education opportunities for students from marginalized groups, particularly refugees.”

"I am incredibly grateful and humbled by this award," says Nyawelo. "It feels great to be recognized and rewarded for the hard work that one does. I am grateful to everyone who has always been a part of my journey, from my family to my colleagues who supported me and showed me how to give back to my community. In particular, I would like to thank my former Dean — Pierre Sokolsky who enthusiastically encouraged me from the very beginning and strongly supported my work to provide opportunities for students from marginalized groups in STEM."

Earlier this year, under the auspices of Nyawelo's INSPIRE program, a community of refugee students and their families, scientists, educators and policymakers celebrated an event three years in the making. As reported in @The U, Nyawelo and his team installed five cosmic ray detectors atop the Department of Workforce Services Utah Refugee Center in downtown Salt Lake City. The detectors, which measure echoes of cosmic particles bombarding Earth’s atmosphere, were built by nearly 60 participants in the program formally called Investigating the Development of STEM-Positive Identities of Refugee Teens in a Physics Out of School Time Experience. INSPIRE brings science research — in this case particle physics — to teenagers and contributes to a worldwide effort to measure cosmic ray activity on Earth. Data from these detectors are added in real-time to a widely available database that has also recently been relocated to U.

"The APS Fellow distinction is given to less than 0.5% of the non-student APS members and is an incredible honor for our department," says Carsten Rott, chair of the Department of Physics and Astronomy. "I am just excited about all the ways that Tino has and continues to enrich our department and give deeper meaning to the importance of STEM education, in many cases making life changing differences for so many students."

A presentation of certificates is done at the annual meeting of the APS forum on Diversity and Inclusion.

By David Pace

Read about Nyawelo's winning last year's international Spirit of Salam Award here. Watch a video about the community cosmic ray deployment in Salt Lake City facilitated by Nyawelo below:

ACCESS Scholar: Kate Anderson

ACCESS Scholar, Kate Anderson


October 1, 2024
Above: Kate Anderson

Undergraduate Kate Anderson has her sights set far, another planet to be exact. After a year of research in the ACCESS Scholars program, she is one step closer to her dream of becoming a NASA astronaut. 

Anderson grew up in Las Vegas, Nevada, and had a passion for science, astronomy specifically, from a young age. She says that ACCESS was what initially drew her to the U, and ultimately what made her decide to major in physics and chemistry. The ACCESS scholarship is designed to advance belonging in STEM by engaging first-year students with research and helping them develop a community within the college.

Like many alumni of the program, ACCESS strongly shaped Anderson’s first year experience. She contributed to a project in Assistant Professor Yao-Yuan Mao’s astrophysics lab. Anderson gathered data with code to locate isolated, low-mass galaxies near the Milky Way that might provide clues to the origin of our universe. 

“Some of these galaxies are so isolated from the Milky Way that they have had little to no interaction with other galaxies since their creation. Because of that, they still have a lot of the properties of the very early universe. I was just trying to find the precursor to the bigger question” explains Anderson. 

This hands-on research experience through ACCESS helped Anderson earn a NASA Space Grant Consortium Scholarship, an additional boost on her path to becoming an astronaut. 

Anderson’s dream of voyaging to another planet to do true astrophysics “fieldwork” is supported by a plan that has been in the works since well before she stepped foot on campus. “I decided I wanted to be an astronaut and worked backwards,” she says. 

NASA astronauts either have a science or military background. Anderson thought “why not both?”. This motivated her to join the Air Force ROTC in addition to her academic obligations with the hope of becoming a pilot. This way, she can command the spaceship as well as handle the science. 

“NASA actually posted applications for astronauts a couple months ago. I was devastated that I couldn't apply now,” says Anderson. Though the journey ahead is long, this budding scientist and future space traveler has a lot to look forward to in her next few years at the U. Anderson is excited about starting  new research projects, taking observational astronomy, and spending time with her friends, many of whom she met through ACCESS. 

By Lauren Wigod

How special is the Milky Way Galaxy?  

How special is the Milky Way Galaxy?


September 25, 2024

Above: A mosaic of the satellite galaxies across the Milky Way-like systems that the SAGA team has surveyed. The images are sorted by their luminosity from left to right. Credit: Yao-Yuan Mao (Utah), with images from the DESI Legacy Surveys Sky Viewer

A 'saga' about 101 galaxies like the Milky Way and their companions

Is our home galaxy, the Milky Way Galaxy, a special place? A team of scientists started a journey to answer this question more than a decade ago. Commenced in 2013, the Satellites Around Galactic Analogs (SAGA) Survey studies galaxy systems like the Milky Way. Now, the SAGA Survey just published three new research articles that provide us with new insights into the uniqueness of our own Milky Way Galaxy after completing the census of 101 satellite systems similar to the Milky Way’s.   

These “satellites” are smaller galaxies in both mass and size which orbit a larger galaxy, usually called the host galaxy. Just as with smaller satellites that orbit the Earth, these satellite galaxies are captured by the gravitational pull of the massive host galaxy and its surrounding dark matter. The Milky Way Galaxy is the host galaxy of several satellite galaxies, of which the two largest are the Large and Small Magellanic Clouds (LMC and SMC). While LMC and SMC are visible to the naked eye from the Southern Hemisphere, there are many other fainter satellite galaxies orbiting around the Milky Way Galaxy that can only be observed with a large telescope.  

The goal of the SAGA Survey is to characterize satellite systems around other host galaxies that have similar stellar masses as the Milky Way Galaxy. Yao-Yuan Mao, a University of Utah faculty member in the Department of Physics and Astronomy, is co-leading the SAGA Survey with Marla Geha at Yale University and Risa Wechsler at Stanford University. Mao is the lead author of the first article in the series of three that have all been accepted by the Astrophysical Journal. This series of articles reports on the SAGA Survey’s latest findings and makes the survey data available to other researchers worldwide.  

 An outlier galaxy? 

An image of a Milky Way-like galaxy and its system of satellite galaxies. The SAGA survey identified six small satellite galaxies in orbit around this Milky Way analog. Credit: Yasmeen Asali (Yale), with images from the DESI Legacy Surveys Sky Viewer https://www.legacysurvey.org/acknowledgment/

 In the first study led by Mao, the researchers highlighted 378 satellite galaxies identified across 101 Milky Way-mass systems. The number of confirmed satellites per system ranged from zero to 13 — compared to four satellites for the Milky Way. While the number of satellite galaxies in the Milky Way system is on par with the other Milky Way-mass systems, “the Milky Way appears to host fewer satellites if you consider the existence of the LMC,” Mao said. The SAGA Survey has found that systems with a massive satellite like the LMC tend to have a higher total number of satellites, and our Milky Way seems to be an outlier in this regard. 

An explanation for this apparent difference between the Milky Way and the SAGA systems is the fact that the Milky Way has only acquired the LMC and SMC quite recently, compared with the age of the universe). The SAGA article explains that if the Milky Way Galaxy is an older, slightly less massive host with the recently added LMC and SMC, one would then expect a lower number of satellites in the Milky Way system not counting other smaller satellites that LMC/SMC might have brought in.  

This result demonstrates the importance of understanding the interaction between the host galaxy and the satellite galaxies, especially when interpreting what we learn from observing the Milky Way. Ekta Patel, a NASA Hubble Postdoctoral Fellow at the U but not part of the SAGA team, studies the orbital histories of Milky Way satellites. After learning about the SAGA results, Patel said, “Though we cannot yet study the orbital histories of satellites around SAGA hosts, the latest SAGA data release includes a factor of ten more Milky Way-like systems that host an LMC-like companion than previously known. This huge advancement provides more than 30 galaxy ecosystems to compare with our own, and will be especially useful in understanding the impact of a massive satellite analogous to the LMC on the systems they reside in.”  

Why do galaxies stop forming stars? 

The second SAGA study of the series is led by Geha, and it explores whether these satellite galaxies are still forming stars. Understanding the mechanisms that would stop the star formation in these small galaxies is an important question in the field

Yao-Yuan Mao

of galaxy evolution. The researchers found, for example, that satellite galaxies located closer to their host galaxy were more likely to have their star formation “quenched,” or suppressed. This suggests that environmental factors help shape the life cycle of small satellite galaxies.  

The third new study is led by Yunchong (Richie) Wang, who obtained his PhD with Wechsler. This study uses the SAGA Survey results to improve existing theoretical models of galaxy formation. Based on the number of quenched satellites in these Milky Way-mass systems, this model predicts quenched galaxies should also exist in more isolated environments — a prediction that should be possible to test in the coming years with other astronomical surveys such as the Dark Energy Spectroscopic Instrument Survey.  

Gift to the astronomy community 

In addition to these exciting results that will enhance our understanding of galaxy evolution, the SAGA Survey team also brings a gift to the astronomy community. As part of this series of studies, the SAGA Survey team published new distance measurements, or redshifts, for about 46,000 galaxies. “Finding these satellite galaxies is like finding needles in a haystack. We had to measure the redshifts for hundreds of galaxies to just identify one satellite galaxy,” Mao said. “These new galaxy redshifts will enable the astronomy community to study a wide range of topics beyond the satellite galaxies.”  

The SAGA Survey was supported in part by the National Science Foundation and the Heising-Simons Foundation. Other authors of these three SAGA studies include Yasmeen Asali, Erin Kado-Fong, Nitya Kallivayalil, Ethan Nadler, Erik Tollerud, Benjamin Weiner, Mia de los Reyes, John F. Wu, Tom Abel, and Peter Behroozi. 

By David Pace

The Art and Science of Innovation: Catmull’s Story

The Art and Science of Innovation: Catmull’s Story


Sep 16, 2024
Above : Edwin Catmull, co-founder of Pixar. | Pixar

Ed Catmull doesn’t have the intense presence one might expect from a man with his resume.

Not only has Catmull [BS’69, physics] won five Academy Awards, he’s also received an ACM A.M. Turing Award — considered the Nobel Prize of computing — has rubbed shoulders with George Lucas and Steve Jobs, co-founded Pixar and co-created the first computer-animated film (and the technology that made it possible).

Catmull is the 2024 winner of The Leonardo Award, an award that seeks to honor individuals who have made “contributions (that) exemplify the blend of art and science,” per The Leonardo.

To receive his Leonardo Award, Catmull returned to Salt Lake City — the very place his impressive career started.

“(Catmull) credits the atmosphere and the work that he did at the University of Utah with some of his early success,” Virginia Pearce, director of the Utah Film Commission, said during Thursday night’s ceremony. “We are so proud about your start in Utah and the deeply grateful for the mark that you’ve made on (the film industry) industry and beyond.”

‘It was amazing’: How the University of Utah shaped Catmull’s career

As a kid, Catmull balanced his interests in both art and science. He never saw the subjects as being inharmonious.

“Growing up, I didn’t know that (science and art) were considered to be not compatible with each other. Nobody told me that,” Catmull said Thursday night at The Leonardo Museum. Animation fascinated him, but there was no college for it. So when he started his Bachelor’s degree at University of Utah, he fell back on science.

“There were no tools for it, for animation, so I switched over into physics when I went to college,” Catmull said. This revelation prompted laughter from the audience — how can the man who co-founded Pixar be a physicist?

Read the full article by Margaret Darby in DeseretNews.