When U.S. Rep. Earl L. “Buddy” Carter from Georgia’s 1st District visited Atlanta recently, one of his top priorities was meeting with the experts at Georgia Tech’s 20,000-square-foot Advanced Manufacturing Pilot Facility (AMPF).

Carter was recently named the House Energy and Commerce Committee’s chair of the Environment, Manufacturing, and Critical Materials Subcommittee, a group that concerns itself primarily with contamination of soil, air, noise, and water, as well as emergency environmental response, whether physical or cybersecurity.

Because AMPF’s focus dovetails with subcommittee interests, the facility was a fitting stop for Carter, who was welcomed for an afternoon tour and series of live demonstrations. Programs within Georgia Tech’s Enterprise Innovation Institute — specifically the Georgia Artificial Intelligence in Manufacturing (Georgia AIM) and Georgia Manufacturing Extension Partnership (GaMEP) — were well represented.

“Innovation is extremely important,” Carter said during his April 1 visit. “In order to handle some of our problems, we’ve got to have adaptation, mitigation, and innovation. I’ve always said that the greatest innovators, the greatest scientists in the world, are right here in the United States. I’m so proud of Georgia Tech and what they do for our state and for our nation.”

Carter’s AMPF visit began with an introduction by Thomas Kurfess, Regents' Professor and HUSCO/Ramirez Distinguished Chair in Fluid Power and Motion Control in the George W. Woodruff School of Mechanical Engineering and executive director of the Georgia Tech Manufacturing Institute; Steven Ferguson, principal research scientist and managing director at Georgia AIM; research engineer Kyle Saleeby; and Donna Ennis, the Enterprise Innovation Institute’s director of community engagement and program development, and co-director of Georgia AIM.

Ennis provided an overview of Georgia AIM, while Ferguson spoke on the Manufacturing 4.0 Consortium and Kurfess detailed the AMPF origin story, before introducing four live demonstrations.

The first of these featured Chuck Easley, Professor of the Practice in the Scheller College of Business, who elaborated on supply chain issues. Afterward, Alan Burl of EPICS: Enhanced Preparation for Intelligent Cybermanufacturing Systems and mechanical engineer Melissa Foley led a brief information session on hybrid turbine blade repair.

Finally, GaMEP project manager Michael Barker expounded on GaMEP’s cybersecurity services, and Deryk Stoops of Central Georgia Technical College detailed the Georgia AIM-sponsored AI robotics training program at the Georgia Veterans Education Career Transition Resource (VECTR) Center, which offers training and assistance to those making the transition from military to civilian life.

The topic of artificial intelligence, in all its subtlety and nuance, was of particular interest to Carter.

“AI is the buzz in Washington, D.C.,” he said. “Whether it be healthcare, energy, [or] science, we on the Energy and Commerce Committee look at it from a sense [that there’s] a very delicate balance, and we understand the responsibility. But we want to try to benefit from this as much as we can.”

“I heard something today I haven’t heard before," Carter continued, "and that is instead of calling it artificial intelligence, we refer to it as ‘augmented intelligence.’ I think that’s a great term, and certainly something I’m going to take back to Washington with me.”

“It was a pleasure to host Rep. Carter for a firsthand look at AMPF," shared Ennis, "which is uniquely positioned to offer businesses the opportunity to collaborate with Georgia Tech researchers and students and to hear about Georgia AIM.

“At Georgia AIM, we’re committed to making the state a leader in artificial intelligence-assisted manufacturing, and we’re grateful for Congressman Carter’s interest and support of our efforts."

ATLANTA — Annoviant Inc. a health technology company and member startup in the Center for MedTech Excellence at Georgia Tech's Enterprise Innovation Institute, is receiving a $2.99 million National Institutes of Health (NIH) grant to further scale the development and commercialization of its TxGuard™ pulmonary-valved conduit for pediatric heart disease.

The award follows two Phase I NIH grants the company received, the most recent being in 2021.

Annoviant's patented TxGuard™ stands at the forefront of technological innovation in conduit replacements for treating congenital heart disease (CHD), the most prevalent birth defect globally and a leading cause of birth-related mortality, the company said.

CHD encompasses a broad range of abnormalities that disrupt blood flow to and from the heart. It affects approximately 40,000 newborns annually — or 1% of births in the U.S. — and 1.35 million worldwide. With an estimated 2.9 million CHD patients in the U.S. alone, the need for advanced solutions is paramount.

"This marks a significant milestone for Annoviant as we accelerate our pursuit of impactful innovation to save lives," said Annoviant CEO and co-founder Ajay Houde, Ph.D. "It validates our hypothesis and shows the NIH's confidence in our ability to make good progress. Because we are a small startup, it gives private investors the confidence to invest with us and more companies working with us across the broader ecosystem."

Addressing critical shortcomings observed in current commercial devices, TxGuard™ offers clinical advantages, notably its resistance to calcification, thrombosis, infection, and the host cell integration. This cutting-edge technology marks a new era in pediatric cardiac interventions, providing durable pulmonary valved grafts that adapt and regenerate alongside patients, minimizing the need for multiple re-operations over their lifetimes.

"Heart disease is the leading killer of men and women in the U.S. and is the most common birth defect in our newborns," said Center for MedTech Excellence Director Nakia Melecio, who worked with Annoviant to help it scale and reviewed its federal funding submissions.

The Center for MedTech Excellence, which launched in 2022, works with early-stage life sciences startups that have specific obstacles that young tech companies in other sectors don't face.

"This is a critical milestone for the company, and validates its research and work, thus far," Melicio said. "Annoviant's technology is tackling several challenges that the market currently faces and elevating the possibility for better patient outcomes in management of congestive heart failure."

Pediatric patients with CHD often undergo multiple cardiovascular surgeries throughout their lives, with associated costs totaling billions for the U.S. healthcare industry. TxGuard™ offers a transformative solution to this ongoing challenge, promising extended durability and reduced healthcare burden for patients and providers alike.

He credited the company's work with the Center for MedTech Excellence and being a health tech startup in the Advanced Technology Development Center (ATDC), the Enterprise Innovation Institute's startup incubator, as being pivotal in Annoviant's growth.

ATDC SBIR/STTR Catalyst Connie Casteel, who works with the incubator's portfolio companies to help the prepare for these federal, non-dilutive funding grants, had worked with Annoviant on its federal funding approach and strategy.

"We went through the 16-week program with the MedTech Center and it really helped us think through the various aspects of the commercialization process and operational challenges we would face," Houde said. "Greg Jungles at ATDC was also instrumental in helping us.  I'm really thankful for Nakia and his work with the MedTech Center and Greg and the team at ATDC."

“What I’ve repeatedly found is that people are terrified of cyberattacks, because, frankly, cyberattacks are scary,” said Ryan Shandler, assistant professor of political science in Georgia Tech’s School of Cybersecurity and Privacy, where his research focuses on how people react to cyberattacks. “People don’t fully understand them. They don’t know who’s behind them.”

Shandler’s latest study looks at the effect this uncertainty has on public opinion after a cyber incident.

“When faced with the unknown, people conjure visions of doom, where one bad guy in his mom’s basement clicks a button and takes over the world.”

According to Shandler, even a minor cyberattack can generate the kind of fear that “changes world views or causes people to vote a certain way, sacrificing their civil liberties for security and surveillance, regardless of how intrusive.” By way of example, Shandler refers to a digital mishap hyperbolically reported as a major cyberattack on a Florida water plant that actually resulted from an employee mistake.

“These reactions from the general public, even when they don’t know who is behind an attack, can have strong political and societal consequences,” he said.

Shifting the Focus

Sometimes he refers to this uncertainty as “a shadow of ambiguity.” Shandler and his collaborators have added a new element to the body of cyber-conflict literature, most of which deals with ambiguity from an operational or strategic perspective. His team has written an article for a special issue of the Journal of Peace Research that focuses on the uncertainty surrounding cybersecurity incidents. Shandler also co-edited the issue.

The researchers surveyed 2,025 participants, who were asked to evaluate potential cyber threat scenarios and decide on various retaliatory measures.

A typical question presented two scenarios positing a cyberattack on the U.S. In one, intelligence sources might be 70% certain that China was the perpetrator; in the other, intelligence might be 40% certain it was caused by the United Kingdom. Other options in the scenario included the proposed means of retaliation and the chance of conflict escalation. Participants were asked which strategic course they preferred — whether to retaliate and, if so, against whom.

“As the government’s certainty percentage goes down, the level of support for retaliation goes down, which is unsurprising,” said Shandler, whose collaborators on the study were Nathaniel Porter of Virginia Tech and Eric Jardine of cybersecurity firm Chainalysis. “But when we dig a little deeper, we can see that it depends on who the other country is. If we’re 50% sure China is behind it, we tend to lean more toward retaliation than if we’re 50% sure that England is behind it.”

Mental Shortcuts

Faced with the complexities of cyberspace and the potential threats inhabiting it, most people will fall back on mental shortcuts when forced to decide in the face of uncertainty, the researchers assert. As such, perceptions of countries as adversaries or allies play a role in decision-making.

Political partisanship also played a role in how people responded to the scenarios. For Republicans, the perception of another country as an ally or rival mattered more than it did for Democrats. This also wasn’t particularly astonishing to the researchers.

“We didn’t want to guess — we wanted to find out how people react when faced with the ambiguity of a cyberattack,” Shandler said. He and his colleagues hoped to identify what they called a “certainty threshold.”

That is, they wanted to answer a basic question: How sure do authorities need to be about the perpetrator to gain public support for economic, diplomatic, or military responses?  After gathering and crunching the numbers, the researchers put the threshold at 60% certainty, though it shifts depending on the identity of the presumed attacker.

Shandler’s colleagues in the School of Cybersecurity and Privacy are mostly computer scientists who work in bits, bytes, and rational logic — everything is mapped out and orderly, unlike human beings, who aren’t logical or rational.

“People are not computer code. We’re messy, emotional, and use mental shortcuts to make decisions,” Shandler said. “So, we thought a human analysis of the uncertainty that is so much a part of cyberspace would be a good idea.”

Ultimately, Shandler hopes his research will force policymakers and national security officials to pay more attention to the way the public experiences cyber threats, because voters won’t write a blank check and support retaliation in response to every attack.

“When states volley cyberattacks back and forth, the public gets caught in the crossfire, and they need to be a stakeholder in decisions about how to react,” he said.

Authorities should be more open with the public, he added. That would go a long way toward demystifying cyberattacks and avoiding the potential of a mass panic.

“In my experience, mystifying the situation is how we get to the theories of cyber doom and Armageddon and Mission Impossible and the robots coming to get us,” Shandler said. “I think what people are imagining is much worse than the reality. It’s the lack of information that scares them.”

CITATION: Eric Jardine, Nathaniel Porter, Ryan Shandler. "Cyberattacks and public opinion – The effect of uncertainty in guiding preferences," Journal of Peace Research. doi.org/10.1177/0022343323121

More than 400 people participated in Energy Materials Day on March 27, as researchers and industry leaders came together to discuss and advance energy materials technologies such as solar energy, carbon-neutral fuels, and batteries.

Energy materials are the things — natural, manufactured, or both — that aid the use of energy. They also play a key role in developing cleaner, more efficient energy solutions.

Energy Materials Day was co-hosted by Georgia Tech’s Strategic Energy Institute (SEI), the Institute for Materials (IMat), and the Georgia Tech Advanced Battery Center. The event evolved out of last year’s Georgia Tech Battery Day.

“As an engine of innovation in science and technology, Georgia Tech has incredible opportunities and the responsibility to conduct research to benefit society,” said Chaouki Abdallah, executive vice president for Research at Georgia Tech. “We call this ‘research that matters.’”

Events like Energy Materials Day are part of an ongoing, long-range effort to position Georgia Tech, and Georgia, as a go-to location for modern energy companies. Tech was recently ranked by U.S. News & World Report as the top public university for energy research. Abdallah also outlined why Georgia Tech, with more than 1,000 researchers across campus working in the energy space, is a natural fit for events that foster collaboration between the public and private sectors.

“Right here, right now, we have the opportunity to harness our collective powers, our collective knowledge, our collective resources to become a global engine of innovation,” he said.

Plenary speaker Danielle Merfeld, global chief technology officer at QCells, highlighted opportunities for the current and future clean energy infrastructure in the United States.

"At the heart of our discussions today [are these questions]: What is new technology, and how do you make it ... and make it at scale, in an affordable, accessible, and reliable way?” she said.

"... [The] good news is this country has taken a very deliberate step toward creating the most robust industrial policy we've had in decades. ... This is driving opportunity and creating the foundation for manufacturing. So, [we can] use that industrial base of making and consuming power [and] decarbonize the electric grid by 2035...."

“Events like this are so important to forwarding progress in research and industry,” said Eric Vogel, IMat’s executive director. “It’s important to bring together professionals throughout the industry to keep these lines of communication open.”

The day was divided into three tracks: battery materials and technologies, photovoltaics and the grid, and materials for carbon-neutral fuel production. Attendees were encouraged to listen to talks from all three areas. Each track included academic speakers who shared their research and private-sector speakers who described how technological advancements are affecting the industry.

“With its rich history in energy research, Georgia Tech remains a leader in addressing global energy challenges,” said Tim Lieuwen, executive director of SEI. “The success of Energy Materials Day is encouraging, and I eagerly anticipate continuing these discussions in 2025.”

Georgia Tech’s College of Engineering has established an artificial intelligence supercomputer hub dedicated exclusively to teaching students. The initiative — the AI Makerspace — is launched in collaboration with NVIDIA. College leaders call it a digital sandbox for students to understand and use AI in the classroom

Initially focusing on undergraduate students, the AI Makerspace aims to democratize access to computing resources typically reserved for researchers or technology companies. Students will access the cluster online as part of their coursework, deepening their AI skills through hands-on experience. The Makerspace will also better position students after graduation as they work with AI professionals and help shape the technology’s future applications.

“The launch of the AI Makerspace represents another milestone in Georgia Tech’s legacy of innovation and leadership in education,” said Raheem Beyah, dean of the College and Southern Company Chair. “Thanks to NVIDIA’s advanced technology and expertise, our students at all levels have a path to make significant contributions and lead in the rapidly evolving field of AI.”

Read the full story on the College of Engineering website.

The Center for Sustainable Communities Research and Education (SCoRE — formerly SLS), in collaboration with the Strategic Energy Institute (SEI), the Brook Byers Institute for Sustainable Systems (BBISS), the Renewable Bioproducts Institute (RBI), and the Social Equity and Environmental Engineering Lab (SEEEL), launched the Energy Equity, Environmental Justice, and Community Engagement Faculty Fellows Program in November 2023. In this program, Georgia Tech faculty learn how to work with communities, bringing together their academic knowledge and the local expertise of communities that has been developed through lived experience and long-standing social action.

The inaugural fellows include 24 Georgia Tech faculty from five Colleges, as well as a faculty colleague from Georgia Gwinnett College and a partner from the Southeast Energy Efficiency Alliance, who are building relationships with each other and with community partners in the areas of energy equity and environmental justice. Since the launch, they have engaged in a wide array of events, including community benefit and development workshops, site visits to community-based organizations across the Atlanta region, and university-community gatherings and symposia.

The program is expected to result in both collective and individual deliverables. Collective deliverables include the development of network mapping tools to facilitate collaborations inside and outside Georgia Tech, a set of principles for conducting community-engaged research, a reflective essay on faculty training for community-engaged research, and ideas for future activities to facilitate university-community and interdisciplinary team formation. Fellows individually determine their deliverables, which run the gamut from exploring partnerships for a specific research project to writing a societal impact statement for a tenure package.

More broadly, the program aims to grow Georgia Tech’s collaborative expertise in community-engaged research by forming a supportive network of faculty interested in community-engaged sustainability research and education.  

Faculty Affiliate: Patritsia Stathatou, Research Scientist, Renewable Bioproducts Institute, Georgia Tech

Sustainable energy sources and environmental justice go hand in hand. Although such technologies aim to minimize environmental impacts of modern societies, without considering issues of environmental justice and energy equity, these solutions can inadvertently perpetuate disparities by disproportionately benefiting certain communities while harming others. Bridging the gap between technological advancements and community benefits is paramount to creating an equitable energy future for all.

This program provides a unique opportunity to explore these interconnections, enhancing my knowledge in integrating community values and concerns into my research on alternative fuels and renewable energy sources. I am particularly excited about the hands-on approach of the program, which emphasizes listening sessions and workshops, allowing fellows to gain direct insights from various stakeholders. I hope that, through active participation in these sessions, I can further my understanding of the challenges faced by local communities and incorporate these insights into actionable solutions in my research.

In my project, I'm in a group crafting a reflective essay about our experiences with Community Engaged Research training. Our goal is to translate the insights gained from this pilot program into a publishable piece. Additionally, I'm acquiring valuable insights into the development of Broader Impact Statements and Community Benefits Plans, crucial parts of proposals for securing federal funding from NSF and DoE, respectively.

Faculty Affiliate: Sofia Perez-Guzman, Assistant Professor, School of Civil and Environmental Engineering, Georgia Tech

The fellowship program has been a fantastic experience. I never imagined how much I would learn from this program about properly engaging with communities. As researchers, we might think we want to hear the needs that communities face to provide them with solutions. That is different than the way community-driven research should work. I’ve learned that researchers need to gain the communities’ trust, be present and participate in their events, and, more importantly, work at their pace and for their interests rather than push our research agendas for our professional benefit. I know there is still a lot more I must continue learning, but what I’ve learned so far has been an eye-opener that is making me rethink how to approach my research and its social aspect.

My project focuses on the social performance of supply chains, and I am seeking to put more emphasis on the “social” part of my research by making it more community-driven. That is why I applied for the fellowship. I am advancing two current projects as part of the fellowship. One relates to increasing food accessibility to vulnerable populations via community-driven freight transportation solutions. I want to bring food closer to people and do it by co-designing solutions with the communities. The second project relates to forming a team to pursue research on enhancing community resilience to extreme weather events for the mobility of people and goods. The fellowship and a Sustainability Next seed grant from BBISS are helping me move forward with this project.

Georgia Institute of Technology (Georgia Tech) researchers have teamed up with The Carter Center to support dracunculiasis eradication efforts, using mathematical modeling and analytics. Dracunculiasis, or Guinea worm disease (GWD), is caused by the parasite Dracunculus medinensis. Currently, there is no diagnostic test to detect pre-patent infection, no vaccine, and no treatment for GWD. Eradication efforts focus on community-based surveillance, health education, targeted treatment of water sources with larvicide, and most importantly, behavioral changes, such as filtering drinking water and preventing humans and animals, mainly domesticated dogs with emerging worms, from entering and contaminating water sources.  “Given the year-long life-cycle of the disease, mathematical modeling is a valuable tool for fine-tuning interventions and evaluating resource allocation decisions,” said Pinar Keskinocak, professor in the School of Industrial and Systems Engineering (ISyE) and the director of the Center for Health and Humanitarian Systems.

Disease Dynamics

Dracunculus medinensis is a parasite that infects in a vicious cycle. When a human or animal host  ingests either water contaminated with infective Guinea worm larvae or raw or undercooked aquatic animals that harbor the infectious larvae, the larvae mate in the host’s body, and, after 10-14 months, a pregnant female worm that can be as long as one meter emerges slowly and painfully from the host’s body. To seek relief, the host might immerse the affected body part into a water source (e.g., a pond), releasing the worm’s larvae into the water source, contaminating it, and continuing the infection cycle. In particular, worms emerging from dogs can contaminate drinking water sources used by people and in turn, lead to infection of people or other dogs in the community. 

Progress Toward GWD Eradication

GWD eradication efforts worldwide have been supported by the collaboration of many entities, including The Carter Center, ministries of health in endemic countries, WHO, CDC, UNICEF, and others. Since 1986, The Carter Center has led the international Guinea worm eradication campaign, which has eliminated the ancient disease in 16 countries in Africa and Asia. In 2022, Guinea worm was reported in five African countries.

Together with The Carter Center and Chad’s national Guinea Worm Eradication Program, Georgia Tech researchers have developed an agent-based simulation model that incorporates the life-cycle of the worm, daily interactions between dogs and water sources, seasonality of infections, and environmental factors such as rainfall and temperature. The models can also capture the influence of dog movement between multiple regions/water sources. Using these mathematical models in a wide range of simulated scenarios, the researchers evaluated the impact of combinations of interventions (such as water treatment or tethering of dogs). The results from the simulated scenarios suggest that historical levels of interventions in Chad, even when adjusted to regional differences, might not be sufficient to interrupt GWD transmission in dogs within the next five years. Hence, there is a need to improve intervention implementation fidelity, adjust implementation approaches, or implement new interventions.

GWD Eradication Onward

New interventions, such as a diagnostic test that can detect pre-patent infection, could help accelerate the progress toward eradication.  To guide research and development of such a test, WHO initiated the development of target product profiles (TPPs), outlining preferred and minimally acceptable criteria for novel diagnostic tests, which could be, according to WHO, “a game changer in speeding up a global eradiation of the parasite.”

Georgia Tech researchers adapted an agent-based simulation model and evaluated a wide range of scenarios to assess the impact of a new diagnostic test to detect pre-patent infection in dogs on the disease spread. In the mathematical model, each dog is represented by an "agent," which mimics the dog behavior, their interactions with the water source, and the progression of the disease within a dog.

In the absence of a treatment for GWD, the research results quantify the impact of the diagnostic accuracy (sensitivity and specificity) of the test, but also emphasize the importance of rollout decisions and the compliance of dog owners with the recommended tethering practices. “The potential benefits of testing depend on test accuracy, but also on several other factors, e.g., how the test is deployed, and how it affects owners’ behaviors regarding tethering of dogs with positive or negative test results,” said Hannah Smalley, a research engineer in ISyE. “For example, even if the test could detect pre-patent infections in dogs with perfect accuracy, if dogs are not tested frequently enough, or if owners do not consistently tether test-positive dogs, then the impact of such a diagnostic test could be limited.” The timing of when, i.e., how far in advance of worm emergence, the test can detect pre-patent infection is also important. For example, if the test could not only detect pre-patent infection but also accurately estimate the timing of worm emergence, this could increase the owners’ compliance with tethering recommendations during the time period leading to estimated worm emergence, reduce the need for long-term tethering, and reduce the resources (human and financial) needed to support the intervention.

Recommendations from the research are included in the WHO’s TPP for a diagnostic test to detect pre-patent Guinea worm infections in animals. “This important research highlights how a novel diagnostic test that can detect pre-patent Guinea worm infections could help, especially if used in conjunction with existing interventions,” said Adam Weiss [Director of The Carter Center’s Guinea Worm Eradication Program], “and we are looking forward to continuing our collaborations with Georgia Tech as a means to support GWD eradication efforts.”

Effective July 1, Eric Vogel will become the executive director of the Institute for Matter and Systems (IMS), Georgia Tech’s newest Interdisciplinary Research Institute (IRI) that will launch on the same date.

As an evolution of the Institute for Materials (IMat) and the Institute for Electronics and Nanotechnology (IEN), IMS aims to enable convergent research at Georgia Tech related to the science, technology, and societal underpinnings of innovative materials and devices. Additionally, IMS seeks to integrate these innovations into systems that enhance human well-being and performance across information and communication, the built environment, and human-centric technologies that improve human health, wellness, and performance.

“Executive Vice President for Research Chaouki Abdallah and I are very excited about the launch of IMS, which positions Georgia Tech for integration of science and technology from atoms to devices, while explicitly drawing in researchers in the social sciences, design, business, and computing,” said Vice President of Interdisciplinary Research Julia Kubanek.

“IMS will ensure relevance across Georgia Tech through its newly configured Internal Advisor and Ambassador Board with representation across all six Colleges and GTRI,” she said. “Additional advisory committees representing IMS employees and facility users will ensure that we don’t sacrifice any of the research excellence for which IEN and IMat are known. With IMS I expect we will be even better positioned to tackle research problems that will have the greatest positive societal impact.”

Vogel will continue in his current position as the executive director of IMat until the launch of IMS. In addition to leading and growing IMat, Vogel is the Hightower Professor of Materials Science and Engineering at Georgia Tech’s School of Materials Science and Engineering, and he served as the IEN deputy director prior to leading IMat.

“It is an honor to be appointed executive director of the Institute for Matter and Systems, and I look forward to collaborating with the talented faculty and staff associated with it,” said Vogel. “This opportunity allows us to leverage the core competencies of IEN and IMat while extending our capabilities beyond nanotechnology and materials science. Together, we will be a hub for interdisciplinary research ranging from advanced materials to complex systems that solve global challenges.”

Georgia Tech’s IRIs facilitate collaboration between researchers and students from its six Colleges, the Georgia Tech Research Institute, national laboratories, and corporate entities to tackle critical topics of strategic significance for the Institute as well as for local, state, national, and international communities. IMS will also house and maintain the state-of-the-art Materials Characterization Facility and one of the largest academic cleanrooms in the nation, which offers a broad range of fabrication capabilities from basic discovery to prototype realization.

Before joining Georgia Tech in 2011, Vogel was an associate professor of materials science and engineering and electrical engineering at the University of Texas at Dallas. During this time, he also served as the associate director of the Texas Analog Center of Excellence and led UT Dallas’s involvement in the Southwest Academy for Nanoelectronics.

Prior to UT Dallas, he led the CMOS and Novel Devices Group and established the Nanofabrication Facility at the National Institute of Standards and Technology. Vogel holds a Ph.D. in electrical engineering from North Carolina State University and a B.S. in electrical engineering from the Pennsylvania State University. His research focuses on the development and fundamental understanding of electronic and nanomaterials and devices.

This story was first published in the LIGO newsroom at CalTech.

In May 2023, shortly after the start of the fourth LIGO-Virgo-KAGRA observing run, the LIGO Livingston detector observed a gravitational-wave signal from the collision of what is most likely a neutron star with a compact object that is 2.5 to 4.5 times the mass of our Sun. Neutron stars and black holes are both compact objects, the dense remnants of massive stellar explosions.

What makes this signal, called GW230529, intriguing is that the mass of the heavier object falls within a possible mass-gap between the heaviest known neutron stars and the lightest black holes. The gravitational-wave signal alone cannot reveal the nature of this object, and future detections of similar events, especially those accompanied by bursts of electromagnetic radiation, could hold the key to solving this cosmic mystery.

"Gravitational waves offer an unprecedented glimpse into the cosmos, allowing us to study black holes and neutron stars at vast intergalactic distances," says Surabhi Sachdev, an assistant professor in the School of Physics at Georgia Tech and co-chair of the compact binary coalescence working group for the LIGO Scientific Collaboration. 

"These cosmic messengers are unveiling a surprising population of compact objects with masses that defy our previous understanding based solely on electromagnetic observations," Sachdev explains. "The latest in this list is GW230529, a compact object with a mass that falls within the theorized 'mass gap' between neutron stars and black holes – a region once thought to be devoid of such objects. The ability to peer through this new window is reshaping our knowledge of the densest objects in the universe."

The mass gap between neutron stars and black holes

Before the detection of gravitational waves in 2015, the masses of stellar-mass black holes were primarily found using x-ray observations while the masses of neutron stars were found using radio observations. The resulting measurements fell into two distinct ranges with a gap between them from about 2 to 5 times the mass of our Sun. Over the years, a small number of measurements have encroached on the mass-gap, which remains highly debated among astrophysicists. 

Analysis of the signal GW230529 shows that it came from the merger of two compact objects, one with a mass between 1.2 to 2.0 times that of our Sun and the other slightly more than twice as massive. While the gravitational-wave signal does not provide enough information to determine with certainty whether these compact objects are neutron stars or black holes, it seems likely that the lighter object is a neutron star and the heavier object a black hole. Scientists in the LIGO-Virgo-KAGRA Collaboration are confident that the heavier object is within the mass gap.  

Gravitational-wave observations have now provided almost 200 measurements of compact-object masses. Of these, only one other merger may have involved a mass-gap compact object – the signal GW190814 came from the merger of a black hole with a compact object exceeding the mass of the heaviest known neutron stars and possibly within the mass gap. 

“With the observation of GW230529, comes excitement, not just for this observation, but future observations as well," says Megan Arogeti, a graduate student in the School of Physics at Georgia Tech working on post-merger signals from compact binary mergers. 

"With every observed gravitational wave signal with at least one neutron star progenitor, we have an opportunity to further our understanding of extremely dense nuclear matter," Arogeti says. "As our detector sensitivity increases, we can hope to observe more gravitational waves from the collision of neutron stars and black holes as well as the collision between two neutron stars, which could potentially feature a special postmerger signal allowing us to probe nuclear matter in a higher mass regime than we have been able to so far."

The fourth observing run with more sensitive detectors

The highly successful third observing run of the gravitational-wave detectors ended in spring 2020, bringing the number of known gravitational-wave detections to 90. Before the start of the fourth observing run O4 on May 24, 2023, the LIGO-Virgo-KAGRA researchers made improvements to the detectors, the cyberinfrastructure, and the analysis software that allow them to detect signals from further away and to extract more information about the extreme events in which the waves are generated. 

Just five days after the launch of O4, things got really exciting. On May 29, 2023, the gravitational-wave signal GW230529 passed by the LIGO Livingston detector. Within minutes, the data from the detector was analyzed and an alert (designated S230529ay) was released publicly announcing the signal. Astronomers receiving the alert were informed that a neutron star and a black hole most likely merged about 650 million light-years from Earth. Unfortunately, the direction to the source could not be determined because only one gravitational-wave detector was observing at the time of the signal.

The fourth observing run is planned to last for 20 months including a couple of months break to carry out maintenance of the detectors and make a number of necessary improvements. By January 16, 2024, when the commissioning break started, a total of 81 significant signal candidates had been identified. GW230529 is the first of these to be published after detailed investigation.

Resuming the observing run

The fourth observing run will resume on April 10, 2024 with the LIGO Hanford, LIGO Livingston, and Virgo detectors operating together. The run will continue until February 2025 with no further planned breaks in observing. The sensitivity of the detectors should be slightly increased after the break.  

While the observing run continues, LIGO-Virgo-KAGRA researchers are analyzing the data from the first half of the run and checking the remaining 80 significant signal candidates that have already been identified. By the end of the fourth observing run in February 2025, the total number of observed gravitational-wave signals should exceed 200.

Gravitational-wave observatories

LIGO is funded by the NSF, and operated by Caltech and MIT, which conceived and built the project. Financial support for the Advanced LIGO project was led by NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,600 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. Additional partners are listed at https://my.ligo.org/census.php.

The Virgo Collaboration is currently composed of approximately 880 members from 152 institutions in 17 different (mainly European) countries. The European Gravitational Observatory (EGO) hosts the Virgo detector near Pisa in Italy, and is funded by Centre National de la Recherche Scientifique (CNRS) in France, the Istituto Nazionale di Fisica Nucleare (INFN) in Italy, and the National Institute for Subatomic Physics (Nikhef) in the Netherlands. A list of the Virgo Collaboration groups can be found at: https://www.virgo-gw.eu/about/scientific-collaboration/. More information is available on the Virgo website at https://www.virgo-gw.eu.

KAGRA is the laser interferometer with 3 km arm-length in Kamioka, Gifu, Japan. The host institute is Institute for Cosmic Ray Research (ICRR), the University of Tokyo, and the project is co-hosted by National Astronomical Observatory of Japan (NAOJ) and High Energy Accelerator Research Organization (KEK). KAGRA collaboration is composed of over 400 members from 128 institutes in 17 countries/regions. KAGRA’s information for general audiences is at the website https://gwcenter.icrr.u-tokyo.ac.jp/en/. Resources for researchers are accessible from http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA.