Senior Success: Samantha Lomuscio, Cosmic Gamma-Ray Hunter
Exploring remote, exotic locations is a long-standing tradition among college students. For applied physics major Samantha Lomuscio ’20, that destination during her senior year has been Jupiter, nearly 390 million miles away.
Working with astrophysicists at the American Museum of Natural History (AMNH), where she began conducting high-energy astrophysics research last summer, her goal has been to detect the solar system’s largest planet in a way that has never been done successfully — through gamma-ray emissions.
With a billion times the energy of visible light, these emissions can reveal phenomena from the supernova explosions, solar flares, merging neutron stars, supermassive black holes and cosmic rays that produce them. Lomuscio says she chose Jupiter because its magnetic field structure is similar to red dwarf stars, which are the most abundant stars in the Milk Way Galaxy and capable of hosting planets that potentially support life.
Her exploration at the AMNH began when she became one of eight students selected last year to participate in the National Science Foundation’s Research Experiences for Undergraduates (NSF REU) program for the physical sciences.
“We had no precedent to follow for this study, so the project has been an exciting challenge,” said Lomuscio, an Albert Dorman Honors student and Barry M. Goldwater Scholar from Fair Lawn, N.J. “Ideally, we’d directly study how the dynamics of gamma-ray emissions and the intense magnetic fields of these stars might affect or pose threats to this possibility, but these stars are too far away so we turn to Jupiter for our studies.”
Stretching nearly 30 million kilometers wide, Jupiter’s magnetosphere — the region of space controlled by Jupiter’s intense magnetic field — is among the largest objects in the solar system and is strong enough to trap and accelerate charged particles within its field, producing belts of radiation thousands of times stronger than Earth’s Van Allen belts. Lomuscio says that streams of high-energy particles accelerated to almost the speed of light, known as cosmic rays, may propagate within Jupiter’s magnetosphere and interact with the gas-rich atmosphere of the planet, creating nuclear reactions that generate gamma-rays.
Adding to the excited particle activity are volcanoes on Jupiter’s nearest moon, Io, which are capable of spitting out ions that can create a ring of charged particles around the planet.
“These charged particles can get trapped bouncing back and forth between poles of Jupiter’s magnetosphere, accelerating to the point where they emit radiation,” said Lomuscio. “Charged particles could also be channeled onto Jupiter through its electrical connection with Io orbiting around it, and that is something we’ve wanted to learn more about as well.”
Under the mentorship of Timothy Paglione, a professor of physics and astronomy at York College/CUNY and resident research associate at AMNH, she obtained nine years of gamma ray emission data recorded by NASA’s Fermi Gamma-ray Space Telescope — an international space observatory that images high-energy particles. She quickly discovered an obstacle.
“As time passes, Jupiter appears to traverse the sky … the Fermi telescope generates an all-sky image that captures photon counts every three hours called a gamma-ray counts map, but it was not designed to track an individual object as it moves over time,” said Lomuscio. “Also, in its transit, Jupiter crosses paths with the galactic plane, the Sun, the Moon and a few other strong gamma-ray sources that completely drown out a potential source to detect from Jupiter.”
To resolve the problem, Lomuscio developed a Python routine to generate the coordinates of any solar system object as defined in NASA’s Jet Propulsion Laboratory’s library, syncing that with Fermi’s all-sky image data. She also modified her tracking routine, programming a filter that excluded gamma-ray data when Jupiter was near a bright gamma-ray source, such as the Sun.
“We are trying to detect a clear congregation of photons at Jupiter, which would indicate a gamma-ray source. So far, we have been able to successfully use our routine with Fermi to track gamma-ray signatures that follow Jupiter’s coordinates each day over a nine year period,” explained Lomuscio. “We haven’t received a clear detection yet due to the very bright sources behind Jupiter, so we are modifying our tracking routine to essentially filter out the nine-year gamma-ray record from Jupiter’s background. We’re hopeful this will finally give us a clear detection.”
Lomuscio will continue working on the problem remotely with the museum throughout the summer, up until the next phase of her research career. She’s recently been accepted to the University of Virginia, where she’s ready to pursue a Ph.D. in Astronomy.
“Looking back, my AMNH experience gave me the opportunity to learn about high-energy astrophysics and the mechanisms behind gamma-ray emission in more in depth than ever,” said Lomuscio. “It’s given me scientific knowledge that I will take with me through graduate school, but it’s also helped me affirm that I want to pursue science and astrophysics research as my career, and helped me develop confidence in myself that I am capable of accomplishing this in the future.”
