The School of Physics will launch the new B.S. in Astrophysics program in summer 2025. This new major is the latest addition to the College of Sciences’ academic offerings and responds to increased student demand for courses and research opportunities in astrophysics. A minor in astrophysics will also be offered starting next summer.

According to David Ballantyne, associate chair for Academic Programs and professor in the School of Physics, the new major is unique because it focuses on the future of astronomy and astrophysics, especially in the era of discoveries made by the James Webb Space Telescope and the Laser Interferometer Gravitational-Wave Observatory (LIGO).

“We made a concerted effort when crafting this degree to make it modern and forward-facing,” says Ballantyne. “It is very much focused on the next decade of astronomy and astrophysics, providing a strong emphasis on computational skills, data analysis, and big data.”

The new degree includes coursework on the fundamental physical processes and laws that govern planetary systems, stars, galaxies, and the Universe as a whole. These core topics are complemented by training in computational and data analysis techniques that can be applied to a variety of disciplines. 

For Ballantyne, the degree program should appeal to students who are interested in pursuing careers in space science research as well as those interested in non-research career paths. 

“This program prepares students to solve complex problems in a very quantitative, rigorous way. Such problem solving and computational skills are highly marketable for a range of career paths,” he adds.

The evolution of astrophysics at Tech 

While astronomy coursework and outreach have long existed at the Institute, astrophysics officially began in 2008, when the School of Physics launched the Center for Relativistic Astrophysics (CRA). Today, the Center boasts more than a dozen faculty and research scientists, with expertise spanning high-energy astrophysics, extrasolar planets, gravitational-wave astronomy, and astroparticle physics.

As the CRA’s faculty roster grew, the School expanded its offering of astrophysics courses. A concentration in astrophysics for physics majors was launched during the 2013-14 academic year. A short time later, the School introduced an astrophysics certificate for non-majors. The new astrophysics major and minor — which will replace the concentration and certificate, respectively — reflects a new chapter in the history of astrophysics education and research at Georgia Tech.  

“Most of our peer institutions have an astronomy or astrophysics degree so the creation of this program at Georgia Tech was a natural fit,” says Ballantyne. “Our program fills a critical need considering that there are few options in the U.S. Southeast for students to obtain this type of training at an institution of Georgia Tech’s caliber.”

Declaring the astrophysics major and minor

Current students

Current students can declare the astrophysics major starting next semester, following the standard major change process for undergraduates. The astrophysics minor will be available to all Georgia Tech undergraduates starting summer 2025.

Incoming students

Astrophysics will be added to the list of majors beginning with the admissions application for Summer 2025 (transfer students) and the 2026-27 academic year (first-year students). 

In the interim, transfer students enrolling for the Spring 2025 semester should follow the standard major change process for undergraduates. Students applying to Georgia Tech for the 2025-26 academic year should select “physics” as their major during the application process and choose “astrophysics” once admitted, during the major confirmation process. 

Julia Speicher, a fifth-year Ph.D. graduate student of Professor David Ballantyne, has received the competitive Kavli Institute for Theoretical Physics (KITP) Graduate Fellowship. As a part of Speicher’s fellowship, she will be a fully-funded resident of KITP from January to June 2024. There she will broaden her knowledge of the latest advances in astrophysics, overlapping with several long-term programs held at KITP at the University of California at Santa Barbara, under the mentorship of Prof. Omar Blaes.

Speicher studies the X-ray bursts from neutron stars, using sophisticated simulations on high-performance computing platforms. These simulations evolve the accretion disk around a neutron star, including the effects of general relativity, radiation transport, and hydrodynamics. Speicher has published three journal articles to date and has presented her work at several international conferences. Her research on X-ray bursts is essential to explain and interpret these observed extreme events and to understand the inner workings of accretion flows in a strong gravity regime near neutron stars.

Retired engineer Tom Crowley proves that you can play around with a hobby you love and see it grow into something extraordinary.

The 80-year-old has turned his love of astronomy into consulting work with the Georgia Institute of Technology’s Aloha Telescope outreach program. He operates the robotic telescope on Maui through high-speed internet connections from his home in Park Springs, a senior life plan community in Stone Mountain.

Crowley works in partnership with James Sowell, a Georgia Tech principal academic professional and astronomer in the School of Physics, and director of the university’s observatory.

Together, they’re bringing live video images of the moon into Georgia K-12 classrooms.

The oohs and ahhs they get in return are priceless.

“I tell kids this is almost as close as operating the Hubble Space Telescope or the rover on Mars,” Crowley said. “This telescope is almost a quarter of a way around the world.”

When he’s at home, Crowley runs the telescope through his computer and keeps the image online throughout the day. He also helps with maintenance, sometimes with a trip to its location at the U.S. Air Force Research Lab on Maui.

“It’s the same as if I were sitting at the telescope and using it,” Crowley said. “The fact that it’s 6,000 miles away is not a big deal. I typically get on somewhere between 1 or 2 in the morning (Hawaiian time) and run it to about 6 o’clock.”

Crowley had a long career as an electrical engineer and retired early from IBM. At age 55, he became interested in radio astronomy, studying celestial objects at radio frequencies.

Now, “it’s an obsession,” said Crowley, the past president of the Society of Amateur Radio Astronomers. “This allows me to get back to the purity of engineering.”

Sowell and Crowley met 15 years ago at the Atlanta Astronomy Club. Sowell was the guest speaker and sat across from Crowley during the dinner. Crowley offered to fix the professor’s problems with his telescopes, and they’ve been working together ever since.

“I couldn’t do this without him,” Sowell said.

A gigantic observatory buried in the Antarctic ice has helped scientists trace elusive particles called neutrinos back to their origins at the heart of a nearby galaxy—offering a new way to study a supermassive black hole shrouded from view.

For the first time, an international team of scientists have found evidence of high-energy neutrino emission from NGC 1068, also known as Messier 77, an active galaxy in the constellation Cetus and one of the most familiar and well-studied galaxies to date. First spotted in 1780, this galaxy, located 47 million light-years away from us, can be observed with large binoculars. The results, also published (Nov. 4, 2022) in Science, were shared today in an online scientific webinar that gathered experts, journalists, and scientists from around the globe

The detection was made at the National Science Foundation-supported IceCube Neutrino Observatory, a massive neutrino telescope encompassing 1 billion tons of instrumented ice at depths of 1.5 to 2.5 kilometers below Antarctica’s surface near the South Pole. This unique telescope, which explores the farthest reaches of our universe using neutrinos, reported the first observation of a high-energy astrophysical neutrino source in 2018. The source, TXS 0506+056, is a known blazar located off the left shoulder of the Orion constellation and 4 billion light-years away.

“One neutrino can single out a source. But only an observation with multiple neutrinos will reveal the obscured core of the most energetic cosmic objects,” says Francis Halzen, a professor of physics at the University of Wisconsin–Madison and principal investigator of IceCube. He adds, “IceCube has accumulated some 80 neutrinos of teraelectronvolt energy from NGC 1068, which are not yet enough to answer all our questions, but they definitely are the next big step towards the realization of neutrino astronomy.”

Unlike light, neutrinos can escape in large numbers from extremely dense environments in the universe and reach Earth largely undisturbed by matter and the electromagnetic fields that permeate extragalactic space. Although scientists envisioned neutrino astronomy more than 60 years ago, the weak interaction of neutrinos with matter and radiation makes their detection extremely difficult. Neutrinos could be key to our queries about the workings of the most extreme objects in the cosmos.

“Answering these far-reaching questions about the universe that we live in is a primary focus of the U.S. National Science Foundation,” says Denise Caldwell, director of NSF’s Physics Division.

As is the case with our home galaxy, the Milky Way, NGC 1068 is a barred spiral galaxy, with loosely wound arms and a relatively small central bulge. However, unlike the Milky Way, NGC 1068 is an active galaxy where most radiation is not produced by stars but due to material falling into a black hole millions of times more massive than our Sun and even more massive than the inactive black hole in the center of our galaxy.

NGC 1068 is an active galaxy—a Seyfert II type in particular—seen from Earth at an angle that obscures its central region where the black hole is located. In a Seyfert II galaxy, a torus of nuclear dust obscures most of the high-energy radiation produced by the dense mass of gas and particles that slowly spiral inward toward the center of the galaxy.

“Recent models of the black hole environments in these objects suggest that gas, dust, and radiation should block the gamma rays that would otherwise accompany the neutrinos,” says Hans Niederhausen, a postdoctoral associate at Michigan State University and one of the main analyzers of the paper. “This neutrino detection from the core of NGC 1068 will improve our understanding of the environments around supermassive black holes.”

NGC 1068 could become a standard candle for future neutrino telescopes, according to Theo Glauch, a postdoctoral associate at the Technical University of Munich (TUM), in Germany, and another main analyzer.

“It is already a very well-studied object for astronomers, and neutrinos will allow us to see this galaxy in a totally different way. A new view will certainly bring new insights,” says Glauch.

These findings represent a significant improvement on a prior study on NGC 1068 published in 2020, according to Ignacio Taboada, a physics professor at the Georgia Institute of Technology and the spokesperson of the IceCube Collaboration.

“Part of this improvement came from enhanced techniques and part from a careful update of the detector calibration,” says Taboada. “Work by the detector operations and calibrations teams enabled better neutrino directional reconstructions to precisely pinpoint NGC 1068 and enable this observation. Resolving this source was made possible through enhanced techniques and refined calibrations, an outcome of the IceCube Collaboration’s hard work.”

The improved analysis points the way toward superior neutrino observatories that are already in the works.

“It is great news for the future of our field,” says Marek Kowalski, an IceCube collaborator and senior scientist at Deutsches Elektronen-Synchrotron, in Germany. “It means that with a new generation of more sensitive detectors there will be much to discover. The future IceCube-Gen2 observatory could not only detect many more of these extreme particle accelerators but would also allow their study at even higher energies. It’s as if IceCube handed us a map to a treasure trove.”

Snigdaa Sethuram, a Ph.D. graduate student of professor John Wise, has been selected for the Future Investigators in NASA Earth and Space Science and Technology (FINESST) program. The FINESST program awards funding for research projects that are designed and executed by graduate students and contribute to NASA’s science, technology and exploration goals.

Sethuram is the second student in Dr. Wise’s Computational Cosmology group to receive the FINESST award. This fellowship will cover three years of funding for her to complete her thesis project, AI-enhanced Simulations and Synthetic Observations of the First Galaxies and Active Galactic Nuclei. She will be using machine learning techniques to speed up cosmological hydrodynamic simulations of the first galaxies and resolve them further in post-processing, and will be running a large-volume cosmological simulation with her final model.

The final machine learning network is intended for use by anyone simulating early galaxy formation, and synthetic observations of the large-volume simulation should aid in interpreting the James Webb Space Telescope (JWST) observations. Sethuram hopes that the end products will be impactful in generating more resources to understand galactic evolution.

Congratulations to CRA Ph.D. student Kunyang (Lily) Li who was awarded a Gruber Foundation (GF) Fellowship from the International Astronomical Union (IAU). Lily was one of only three winners of this prestigious Fellowship. The title of her winning research proposal is “Implementation of Massive Black Hole Binary Dynamics in Cosmological Simulations”.

This Fellowship will support Lily’s research during her upcoming postdoctoral position at the Institut d’Astrophysique de Paris.

Well done, Lily! We are all proud of you.

Please join us in congratulating Dr. Tamara Bogdanović who was just elected to the Executive Committee of the High Energy Astrophysics Division (HEAD) of the AAS.

Congratulations, Dr. Bogdanović!

Ninety Gravitational Wave Spectrograms and Counting
Image Credit: NSF, LIGO, VIRGO, KAGRA, Georgia Tech, Vanderbilt U.; Graphic : Sudarshan Ghonge & Karan Jani

Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves. Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 — during the first three observing runs. Featured above are the spectrograms — plots of gravitational-wave frequency versus time — of these 90 as detected by the giant detectors of LIGO (in the USA), VIRGO (in Europe), and KAGRA (in Japan). The more energy received on Earth from a collision, the brighter it appears on the graphic. Among many science firsts, these gravitational-radiation chirps are giving humanity an unprecedented inventory of black holes and neutron stars, and a new way to measure the expansion rate of our universe. A fourth gravitational wave observing run with increased sensitivity is currently planned to begin in 2022 December.

School of Physics graduate students and undergraduates analyze new data on ‘wonderful diversity’ of black holes and neutron stars for catalog of gravitational wave events.

An international collaboration of scientists, including a team of Georgia Tech graduate students, undergraduate students, and faculty, has released the largest catalog ever of gravitational waves from cosmic collisions of black holes and neutron stars. 

This week, LIGO–Virgo–KAGRA Collaboration published a set of scientific papers on their findings, which include the detection of 35 new gravitational wave events since the last release, in October 2020. That brings the total number of these observed events to 90 since the first one was detected in 2015.

The gravitational wave findings include confirmation of intermediate-sized black holes, rare black hole-neutron star merges, and more information on extremely distant black holes.

Gravitational waves are ripples in space and time caused by black holes smashing into each other, or neutron stars colliding. Black holes are regions of extremely warped space-time caused by a very compact mass. Intense gravity prevents anything, including light, from escaping. Neutron stars are what’s left of massive stars when all their fuel has been exhausted; they become objects so large and dense (though not as dense as black holes) that atoms cannot sustain their structure as they do on Earth. 

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School of Physics and CRA Ph.D. student Snigdaa Sethuram has been selected by The Simons Foundation for the 2021 Flatiron Institute Center for Computational Astrophysics Pre-Doctoral Program.

The Center for Computational Astrophysics (CCA) at the Flatiron Institute is a vibrant research center in the heart of New York City with the mission of creating new computational frameworks that allow scientists to analyze big astronomical datasets and to understand complex, multi-scale physics in a cosmological context.

Snigdaa, who is part of Dr. John Wise’s Computational Cosmology group, will be working with 3 CCA mentors: Dr. Rachel Cochrane, Dr. Chris Hayward, and Dr. Shy Genel to build the neural network that will emulate the computationally intensive radiative transfer calculations that are traditionally done by high-performance computers on a select set of simulated galaxies. These calculations fully leverage all the simulated information and output observable properties of the galaxies while also significantly reducing the overall cost — enabling more regular comparisons of simulations to observations in the observer space, where the simulation informs the observable properties and not the other way around.

The CCA Pre-Doctoral Program enables graduate student researchers from institutions around the world to participate in the CCA mission by collaborating with CCA scientists for a period of 5 months on site. With this opportunity, Snigdaa and others will be able to participate in the many events at the CCA and interact with CCA scientists working on a variety of topics in computational astrophysics, thereby deepening and broadening their skill sets.

Congratulations Snigdaa, for this outstanding achievement!