Don’t look for a flashy office with a big, mahogany boardroom table. The only mark of the Bartol Research Institute’s presence at the University of Delaware is a small, nondescript sign outside its workshop in the basement of Sharp Laboratory — unless you count the portrait of its second director, the late Martin A. Pomerantz, at the main entrance to Sharp Lab. 

This small-but-groundbreaking assembly of physicists and astrophysicists has an understated presence indeed. It is a cohort as much as anything, a collection of like-minded researchers who pursue knowledge of the universe far beyond Earth.

“Bartol was never a big place,” said William Matthaeus, the Martin A. Pomerantz Chair of Physics and Astronomy at UD. “I think you could call it a scientific research boutique — small and very successful, particularly in the cosmic ray area, and world-renowned.”

The Bartol “boutique” marks its 100th birthday this week, celebrating with almost 100 physicists who are gathering at UD for a three-day Bartol Centennial symposium to talk about everything Bartol focuses on — particle astrophysics, astronomy, space physics and particle physics.

The symposium occurs during the same September week that Bartol was born in 1924. Its formation was announced at the 100th anniversary celebration of the Franklin Institute in Philadelphia, which had received a $1 million gift — a bequest by industrialist Henry Bartol, who died in 1918 — for the establishment of a scientific research endeavor.

Among the speakers at that 1924 party was Ernest Rutherford, considered the father of nuclear physics and one of multiple Nobel laureates who were in attendance, including William Bragg, Pieter Zeeman and Irving Langmuir. Also present at the three-day event was then-UD President Walter Hullihen.

It was an auspicious beginning indeed, and over the past century, many Bartol researchers have led the way in much consequential extraterrestrial research.

Pomerantz, who died in 2008 and is pictured in the Sharp Lab portrait wearing a red parka and standing on ice at the South Pole, is one example. Pomerantz was an explorer and a pioneering astronomer who found optimal conditions for his studies of cosmic rays and solar oscillations at the South Pole. The National Science Foundation named an observatory there after him in 1995.

Matthaeus said he had no idea what the Bartol Research Institute was when Pomerantz recruited him when he was a postdoctoral researcher at NASA’s Goddard Space Flight Center. But the research opportunity described to him seemed like a great fit.

He thinks Bartol’s work is better known internationally than locally.

Astrophysicist Jamie Holder, Bartol director and a professor in the Department of Physics and Astronomy, would agree.

“It’s why I’m here,” said Holder, who studies particle astrophysics and came to UD from Great Britain in 2006. “I had no idea where Delaware was and had never heard of Newark. I certainly had heard of the Bartol Institute…. Part of the reason for this meeting is to raise Bartol’s profile a little bit.”

Philadelphia roots

Bartol’s lineage tracks through its earliest years at the Franklin Institute in Philadelphia and then through nearby Swarthmore College, where it was headquartered under a 50-year agreement.

Bartol’s first director was W.F.G. Swann, who worked mostly in cosmic-ray physics and helped to steer the foundation to Swarthmore’s campus. Researchers developed such instruments as a magnetic spectrograph and built Van de Graaff accelerators and a cyclotron in the late 1930’s.

Development of magnetron cathodes was an important focus during World War II, nuclear physics work expanded after the war, and astronomy and astrophysics were added to the research programs in the 1960s.

Pomerantz was the Bartol director by the time its agreement with Swarthmore expired and helped to steer Bartol’s move to UD in 1977. It arrived as an autonomous unit but is now fully integrated into the College of Arts and Sciences’ Department of Physics and Astronomy.

There were growing pains and financial stresses as the separation from the Franklin Institute unfolded and as UD faculty joined forces with the scientists of the Bartol Institute.

Norman Ness, former director of the Laboratory for Extraterrestrial Physics at NASA’s Goddard Space Flight Center, steered Bartol through some of that during his time at the helm from 1987-2000. Ness, who died in 2023, was an expert in magnetic fields in interplanetary space and was a principal investigator on major missions, including the Voyager spacecraft.

“There were some strong personalities and some strong interactions,” said Stuart Pittel, a nuclear physicist who started at Bartol while it was at Swarthmore and served as its director at UD from 2000-2011. “One of the things I’m most proud of was that when I stepped down as director, I could still count all the people in the institute as friends.”

Stephen Barr, now professor emeritus, steered the ship from 2011-2019, when Holder became its director.

Pittel considers the merger “an unqualified success.”

“We’re fully integrated into the physics department,” Matthaeus said. “We have become the center of activity in what is called the physics of the universe, the half that studies the sun, the solar wind, the magnetosphere, stars and the interstellar medium, cosmic rays and particle physics.”

Ed Nowak, chairman of the department, is an experimental condensed matter and material physicist and not part of Bartol.

“Bartol precedes me at UD,” he said, “but my impression is that it really did broaden and deepen the research profile of the department at UD. It has significantly elevated the global prominence of the department.”

Bartol faculty have contributed to data science, machine learning, artificial intelligence, he said — all of which help to process the large volumes of complex data gathered by observatories and other tools.

“That’s great for the physics community,” Nowak said. “How do you process all of that data and pull out the new physics and new understanding of the universe?”

Expansive research

Bartol accepts applications from department faculty whose research aligns well with its focus on astronomy, astrophysics, space physics and particle physics.

It has about 15 faculty members now, including Matthaeus, whose work in heliophysics includes many major NASA missions, including the Parker Solar Probe, which sent instruments closer to the sun than any spacecraft before it.

Pomerantz planted the UD flag at the South Pole as he pursued his pioneering research there. After his death, Karl Erb, the director of the National Science Foundation's Office of Polar Programs, said Pomerantz “was literally a legend in Antarctic science for his vision and dedication to the field of astronomy.”

Bartol colleagues, led by the late Tom Gaisser — “an unassuming giant,” Pittel called him — gave UD prominence at the IceCube Neutrino Observatory and IceTop facilities, also at the South Pole. Dave Seckel, Serap Tilav and Frank Schroeder continue UD’s leadership work in those projects.

“These are some of the most important experimental programs going on worldwide,” Pittel said.

Bartol members hold leadership positions in many endeavors, such as astrophysicist and Associate Prof. Federica Bianco’s lead role at the Vera Rubin Observatory, an NSF project in Chile.

Holder is involved in the Cherenkov Telescope Array (CTA), a $350 million international collaboration based in Chile and La Palma, Spain.

John Clem, associate professor, and the recently retired Prof. Paul Evenson have used high-altitude scientific balloons for years and have worked to detect neutrons coming from outer space, with a network of monitors around the world, including the roof of Sharp Lab.

Qaisar Shafi, recently retired, was a trailblazer in theoretical high-energy physics and cosmology and was the inaugural Bartol Research Institute Professor of Physics.

Space physics leaders include Matthaeus, Prof. Michael Shay and Bennett Maruca, associate professor.

Prof. Stan Owocki has been a major player in the field of theoretical stellar astrophysics and Prof. Sally Dodson-Robinson brings exciting work in exoplanet studies, Pittel said.

And Veronique Petit, associate professor, brings expertise on massive stars and the new and evolving study of those stars’ magnetic fields.

Building for the future

Looking toward the future includes searching out great new prospects.

“We had quite a few retirements,” Holder said. “But we have been able to hire some new faculty in recent years — exciting and dynamic new faculty with [assistant professors] Arijit Bose, Yan Yang and Spencer Axani.”

Because of this, “I think Bartol will continue to do relatively forefront scientific research,” Pittel said. “I hope they’ll be able to continue to bring in the kinds of people Pomerantz did.”

New faculty bring much fresh potential, different angles of study and plenty of energy for building future projects.

Axani, who joined the faculty in 2022, studies experimental neutrino particle physics, multimessenger particle astrophysics, cosmic rays and nuclear physics.

He was drawn to UD partly because of its Bartol connection. He was aware that the work he was doing at IceCube in Antarctica owed much of its existence to Bartol.

“It’s cool to be part of it now,” said Axani, whose graduate and postdoctoral work was done at MIT. “I look for different physics, but I need to know how the other parts work, how cosmic ray physics works.

“Four years before I came to Bartol, I traveled to the South Pole, and I go into the MAPO building — the Martin A. Pomerantz Observatory — and that’s how I was introduced to Bartol.”

And when established faculty join the team — as Prof. Marianna Safronova recently has done — they bring new insights and collaborative power, too.

Safronova, who joined the UD faculty in 2003, is an expert in quantum physics and didn’t see an intersection with Bartol until recently.

Now, her work with atomic clocks, detection of dark matter, and new quantum technologies have brought new opportunities with particle physicists and astrophysicists.

“There is much quantum can offer to those fields,” she said. “I think curiosity produces more overlap and more possibilities for new opportunities. Life is evolving.”

Such new tools are essential for the physics of the future, Nowak said.

“In terms of high-energy physics and particle physics, the cosmos is the new scientific laboratory,” Nowak said. “Using stars and cosmological events to help us understand the nature of the universe — the tools Marianna is bringing will help reveal the mysteries of the universe.”

Camaraderie is an important piece of the collaborative science and the connections also help students see that they are part of something with historic significance, Holder said.

“Bartol provides a connection back to some really important history in science and physics,” he said. “That can be connections within our particular fields, but for me — a reasonably senior professor — it is still valuable to me when I go to international conferences to say I work as part of the Bartol Research Institute. There is instant name recognition.”

Bartol provides some startup funds for new faculty and distributes significant funds in support of its members’ research. Some goes to help graduate students and postdoctoral researchers, some goes to infrastructure — new equipment, for example — and some is discretionary funding. That could include such things as new hardware, travel support to a meeting or other kinds of seed money.

Holder also has developed a new program to use Bartol funds in support of a Bartol Research Fellow, allowing a postdoctoral researcher three years of secure funding as an independent researcher. The first recipient is Aswathi Balagopal V., who is just starting her work.

“I try to just stay out of their way and let them do great science,” Nowak said. “I’m trying to guide the research profile of the department so we’re not a collection of independent contractors, but we’re all rowing in one direction.

“I’m very happy that we have an Institute like Bartol. It provides excellent resources, supports graduate students and supports the faculty to do great work in their areas of science. We are lucky to have that as part of the department.”