Category: Physics

Physicist’s Search for a New Project Leads to Discovery and Publication

View of the HAWC Observatory with mountains in the background
Data from the HAWC Observatory, shown here, was central to the research project. (Image credit: Jordan Goodman/HAWC Collaboration)

When postdoctoral scholar Xiaojie Wang of the Michigan Technological University Physics Department went looking for her next research topic, she found a previously unexplored region and a path to publication.

Wang is lead corresponding author of the article, “Ultra-High-Energy Gamma-Ray Bubble around Microquasar V4641 Sgr” recently published in Nature journal. The findings highlighted in the article offer new insights into how microquasars might contribute to the cosmic-ray energy spectrum—a long-standing puzzle in astrophysics.

“While reviewing the sky maps in search of my next project, I noticed a region five degrees away from our galactic plane with bright emissions that had not been visible in previous datasets,” said Wang, who works with Petra Huentemeyer, a distinguished professor of physics at Michigan Tech. “No gamma-ray source has been identified nor analyzed in this region—so I seized the opportunity and led the analysis.”

Xiaojie Wang
Xiaojie Wang, who describes the project as both groundbreaking and challenging, relied on collaboration with the close-knit physics community, including other researchers from Michigan Tech.

Huentemeyer’s group focuses on high-energy astrophysical phenomena and low-level data analysis at the High Altitude Water Cherenkov Gamma-ray Observatory (HAWC). The map that caught Wang’s attention was produced by Dezhi Huang, a ’23 Michigan Tech alumnus and previous graduate student in Huentemeyer’s group. Huang was responsible for producing the maps from newly available datasets. Now a postdoc at the University of Maryland, Dezhi continues to work closely with HAWC.

“I shared the discovery with Dezhi and Dr. Huentemeyer, and we were all excited about the potential significance of this new source, especially since no other gamma-ray instruments had reported it. This made the project both groundbreaking and challenging,” said Wang.

“Dr. Huentemeyer has been very supportive, and with the guidance of Dezhi’s current supervisor, Dr. Jordan Goodman, they have contributed greatly to the project’s success,” said Wang. “My role has been central in analyzing the HAWC data, interpreting the results, and collaborating with colleagues from UM-Madison and the Institute of Nuclear Physics Polish Academy of Sciences. Together, we’ve worked to better understand the high-energy emissions from this fascinating source. This project provides new insights into particle acceleration mechanisms in binary systems, and I’m thrilled to have played a key role in this groundbreaking research.”

High-Energy Emissions from a Newly Sighted Microquasar

Wang said the most exciting aspect of the results is the discovery of ultra-high-energy gamma-ray emissions from the microquasar V4641 Sgr. “Microquasars are systems where a black hole or neutron star is pulling material from a nearby star, creating intense radiation and shooting out jets of particles at nearly the speed of light. They’re smaller versions of quasars but still incredibly powerful,” Wang explained. “This is something no other gamma-ray instruments had detected before and marks a major leap in our understanding, as V4641 Sgr is now the first microquasar to show emissions above 200 TeV.” TeV is the abbreviation for teraelectronvolts, a unit of energy equal to one trillion electron volts.

Wang said the discovery pushes the boundaries of what is known about particle acceleration in such systems. “The fact that we detected this using HAWC’s unique capabilities—its wide field of view and continuous sky monitoring—raises new questions about how particles are accelerated in extreme environments like this one,” she said.

Wang said a peanut-shaped emission region researchers observed was another surprising aspect of the findings. “When we analyzed the two parts of this shape, we found nearly identical energy spectra, which strongly suggests they share a common origin—likely the jets or lobes of the microquasar. The photon energies are incredibly high, exceeding 200 TeV, challenging existing models of particle acceleration in microquasars and opening new possibilities for understanding these systems.”

The most current discovery follows previous revelations, including HAWC’s detection of the first discovered microquasar, SS 433, in 2018. That discovery was also led by a Michigan Tech physics research group.

Tracing the Trajectory of the Study

The study started with data from HAWC, the gamma-ray observatory that continuously scans the sky to pick up signals from objects in space, including cosmic rays. When the rays reach Earth’s atmosphere they collide with particles in the atmosphere and create showers of smaller particles known as EAS, or extensive air showers. “Our detectors—large tanks filled with pure water—capture the “Cherenkov lights” produced by these particle showers,” said Wang. “By recording the time and charges, and using advanced techniques like neural networks, we can figure out the type, direction, and energy of the original particles. Once all this is done, tools developed by our team at HAWC help create sky maps, showing where the signals came from and how strong they are. The people responsible for making these maps in HAWC are called map-makers, and Dezhi is one of them.”

Discovering a region in the sky where no gamma-ray studies had been conducted was both exhilarating and challenging. “I applied different statistical models to get a better understanding of the region, estimating how powerful the signal might be. I also spent a significant amount of time searching for possible counterparts—other objects or signals detected in wavelengths like radio, X-ray, and infrared. After carefully reviewing all available data, the microquasar V4641 Sgr emerged as the most likely source responsible for the emissions,” said Wang.

She noted that collaboration was crucial throughout the process. Researchers worked closely with theoretical experts including Huang, Brenda Dingus and Goodman, from the University of Maryland; Ke Fang from the University of Wisconsin-Madison; and Sabrina Casanova from the Institute of Nuclear Physics of the Polish Academy of Sciences sharing data and insights to refine their interpretations.

Wang was recently a guest on the Nature podcast. Listen to the episode “Star-eating black hole could power cosmic particle accelerator.

“Our findings highlight how collaborative efforts and cutting-edge observational tools can push the frontiers of astrophysics,” said Wang. “But we definitely encountered a few surprises and challenges along the way.”

One of the biggest surprises was the extreme energy of the gamma-ray emissions from the microquasar. Wang said it forced researchers to rethink their understanding of how particles are accelerated and transported in such systems. “On the challenge side, the complexity of the emission region was a major obstacle,” she said. Researchers needed more data in order to confidently determine the best-fit statistical model for the peanut-shaped emission. “The HAWC outrigger array—an upgrade to the current detector—or the future SWGO observatory could provide the additional data needed.”

Impact of the Findings Now and In the Future

“Our findings contribute a new piece to the cosmic-ray puzzle, offering valuable insights into how particles are energized and transported across vast distances,” said Wang. “Understanding these processes is crucial not only for advancing astrophysics but also for unraveling the origins of cosmic rays, which have intrigued scientists for over a century.

“While we don’t see immediate real-world applications, the discoveries we make could have long-term and unforeseen impacts. Often, breakthroughs in basic science lead to technological innovations in surprising and unpredictable ways.”

– Xiaojie Wang, Michigan Tech physicist

Next steps for the research include more detailed physical modeling of V4641 Sgr’s emissions, using multi-wavelength data from X-ray, radio, and gamma-ray observatories. “I successfully proposed follow-up observations with the APEX radio telescope in Chile and am now working on another proposal for follow-up observations using NASA and ESA’s X-ray instruments. We also plan to analyze more extensive observation data with the HAWC outrigger array,” said Wang. “These efforts will help refine our understanding of the source’s emission mechanisms and bring us closer to answering long-standing questions about the origins of the universe’s highest-energy particles.”


About the College of Sciences and Arts

The College of Sciences and Arts strives to be a global center of academic excellence in the sciences, humanities, and arts for an increasingly technological world. Our teacher-scholar model provides the foundation for experiential learning, innovative research and scholarship, and civic leadership. The College offers 33 bachelor’s degrees and 25 graduate degrees and certificates. The College conducts approximately $12,000,000 in externally funded research in health and wellness, sustainability and resiliency, and the human-technology frontier.Follow the College on Facebook, Instagram, LinkedInX and the CSA blog. Questions? Contact us at csa@mtu.edu.

Five Alumni Inducted Into College of Sciences and Arts Academy

From left, Leann Nitschke, Carly Robinson, Ping Yang, CSA Dean LaReesa Wolfenbarger, Gary Karicky, and Kimberly Hilton
at the College of Sciences and Arts Academy induction ceremony on Sept. 19. (Image courtesy Kelly Steelman).

Earlier this fall, the Michigan Tech College of Sciences and Arts (CSA) gathered to celebrate the induction of five remarkable and accomplished alumni into the CSA Academy.

Dean LaReesa Wolfenbarger hosted the ceremony honoring these alumni and their contributions to a better tomorrow, which run the gamut from advancing scientific discovery to serving the nation and their communities through defense readiness, healthcare, education, and public engagement.

This year’s CSA Academy inductees are Kimberly Hilton; Gary A. Karicky M.D.; Leann Nitschke, M.D.; Carly Robinson; and Ping Yang.

Kimberly Hilton, '91
Kimberly Hilton, ’91

Hilton, a professor of chemistry at Southwestern Florida State College, is a distinguished science education influencer known as Chemical Kim. Hilton, who makes frequent media and TV appearances, has amassed a following of millions on social media platforms including TikTok, Instagram, and YouTube. Chemical Kim is dedicated to enhancing chemistry education at community colleges and high schools, leveraging technology in science education, and fostering inclusion within the field. Hilton, who earned a BS in chemistry and secondary education certification at Michigan Tech in 1991, was featured in the 2024 issue of Tech Magazine.

Learn more about Hilton in her Michigan Tech Alumni profile.


Gary Krasicky, ’77
Gary Krasicky, ’77

Dr. Gary Krasicky, M.D., graduated from Michigan Tech with high honors, earning a BS in chemistry in 1977. Krasicky went on to complete his studies at the University of Michigan Medical School, where he took specialty training in radiology and nuclear medicine before a four-year Air Force tour as chief of nuclear medicine at Malcolm Grow USAF Medical Center in the Washington, DC area. A Michigan Tech Alumni Board of Managers member from 1982-86, Krasicky entered private practice in 1990, starting a nuclear medicine service at Inova Fairfax Hospital in the radiology practice at Fairfax Radiological Consultants in Northern Virginia. He served as director and radiation safety officer until his retirement in 2004.
Learn more about Krasicky in his Michigan Tech Alumni profile.


Leann Nitschke, ’84
Leann Nitschke, ’84

Dr. Leann Nitschke, M.D., graduated from Michigan Tech in 1984 with a BS in biological sciences. She and fellow ’84 alum Matthew Nitschke married three weeks after graduation and were together for nearly 31 years before Matthew’s passing in 2015. 

She joined the Army National Guard in 1987, serving as a company commander and assistant state surgeon/acting deputy commander of the Illinois state health directorate.

Nitschke earned her M.D. from the Medical College of Wisconsin in 1988 and a master’s of business administration from the University of Massachusetts-Amherst in 2004. After completing her general surgery residency in 1994, Nitschke became board-certified in general surgery, a fellow of the American College of Surgeons, a certified physician executive, and a fellow in the American College of Physician Executives.

Nitschke entered private practice in Effingham, Illinois, serving as chief of surgery and chief of staff. She was on active duty from 2003-2008 at Walter Reed Army Medical Center in Washington, DC, and Fort Drum, New York.

Nitschke retired as a soldier in 2008 with the rank of colonel and entered civil service as a Department of the Army civilian employee. Her civil service career started at Fort Drum, New York as medical director of the Warrior Transition Unit and Medical Evaluation Board service. Next, she served at Fort Carson, Colorado as director of the integrated disability evaluation service, and then at Joint Base Lewis-McChord, Tacoma, Washington as a physician adjudicator for the Physical Evaluation Board. During her tenure at Fort Carson, she served as a member of Rapid Process Improvement / Lean Six Sigma project combining assets from the Veterans Benefit Administration (VBA), Veterans Healthcare Administration (VHA), and Department of Defense (DoD) to develop, test, and fully implement the new integrated disability evaluation process which became the standard across the Army and Veteran Affairs.
Learn more about Nitschke in her Michigan Tech Alumni profile.


Carly Robinson, ’07
Carly Robinson, ’07

Dr. Carly Robinson graduated from Michigan Tech in 2007 with a BS in applied physics. Robinson is the assistant director for information products and services in the U.S. Department of Energy Office of Scientific and Technical Information. She leads multiple teams, including those overseeing the management of DOE research and development (R&D) search tools; curating DOE-funded R&D results and associated information; and providing persistent identifier services for DOE and other federal agencies. Robinson was an AAAS Science and Technology Policy Fellow in both the U.S. Senate and the U.S. Department of Energy Office of Science. Robinson continues to co-author publications on open science practices and gives invited talks in the US and internationally about open science.
Learn more about Robinson in her Michigan Tech Alumni profile.


Ping Yang, ’05
Ping Yang, ’05

Dr. Ping Yang earned her PhD in chemistry at Michigan Tech in 2005. The deputy director of the G.T. Seaborg Institute for Transactinium Science and a staff scientist in the Physics and Chemistry of Materials group of the Theoretical Division at Los Alamos National Laboratory, Yang has extensive experience in computational approaches to modeling electronic structure and reactivity of actinides, surface chemistry, and nanomaterials in solution environments. She has published more than 140 papers and given over 90 invited presentations.

Learn more about Yang in her Michigan Tech Alumni profile

The inductees join a distinguished group of alumni selected as members of the Michigan Technological University Academies. The honor acknowledges their extraordinary achievements as educators, mentors, catalysts, visionaries, and creators that personify the University’s commitment to excellence.

Inductees, nominated by current and emeritus faculty, are selected by consensus based on noteworthy, impactful accomplishments including exemplary public service, outstanding leadership in civic affairs, leading-edge professional performance, and other outstanding contributions to the growth and development of their disciplines within the University and throughout the world.

About the College of Sciences and Arts

The College of Sciences and Arts strives to be a global center of academic excellence in the sciences, humanities, and arts for an increasingly technological world. Our teacher-scholar model provides the foundation for experiential learning, innovative research and scholarship, and civic leadership. The College offers 33 bachelor’s degrees and 25 graduate degrees and certificates. The College conducts approximately $12,000,000 in externally funded research in health and wellness, sustainability and resiliency, and the human-technology frontier.

Follow the College on Facebook, Instagram, LinkedInX and the CSA blog. Questions? Contact us at csa@mtu.edu.

CSA Researchers Participate in first TechTalks

Screen Shot 2016-11-16 at 11.55.24 AMOn Thursday, November 10, 2016, several researchers gave two minute presentations for the inaugural TechTalks session of the Michigan Tech Research Forum. Seven of the 13 researchers presented work from CSA disciplines, including the Distinguished Lecture:

  • Steven Elmer– Department of Kinesiology and Integrative Physiology, Exercise As a Form of Medicine
  • Yang Yang – Department of Mathematical Sciences, Numerical Methods for Partial Differential Equations
  • Selin Philip – Department of Coginitive and Learning Sciences, Creating a Culture of Better Mental/Behavioral Health among the American Indians in the Keweenaw
  • Loredana Valenzano– Department of Chemistry, Molecules, Surfaces, Crystals: A Quantum Chemical Quest from Fundamentals to Applications.
  • Nabanita Saikia – Department of Physics, Emergent Frontiers in 2D Nanomaterials for Biomolecular Recongition and Self-Assembly.
  • Lynn Mazzoleni– Department of Chemistry, Introducing the New 2D-Liquid Chromatograph and High-Resolution Mass Spectrometer in the Chemical Advanced Resoulation Methods (ChARM) Core Facility at Michigan Tech.
  • Tarum Dam – Department of Chemistry, Enriching Health-Related Research Through Glycobiological Approaches.

Michigan Tech Research Forum events are presented by the Office of the Provost and Vice President for Academic Affairs in coordination with the Office of the Vice President of Research. Additional TechTalks sessions are coming up in Spring 2017. Interested in nominating yourself or others? Use this online form.

Browse the Twitter conversations in “TechTalks 2016: Take One,” by Allison Mills.


Distinguished Lecture –image151928-pers

Richelle Winkler gave the inaugural Michigan Tech Research Forum Distinguished Lecture on Thursday, October 13 at 4:00 p.m. in the Memorial Union Alumni Lounge. She discussed Making Research Matter: Democratizing Science and Other Lofty Goals.

Professor Hugh Gorman nominated Winkler, an associate professor of sociology and demography, for “community engaged scholarship” that extends across the Michigan Tech campus. Examples of Winkler’s projects include examining the feasibility—social and technical—of using mine water for geothermal heating systems in Calumet and examining the social, economic, and technical aspects of improving recycling in Houghton County. Both projects involve students and community members, and both have real impact in the communities. Winkler also conducts research on the changing demographics of anglers and hunters—and the implications for policy. She presented on this subject at the Department of Biological Sciences last spring.