Black holes remain one of the most mysterious and intriguing objects in our universe.
One of the newest celestial objects to be studied — they were only first theorized in the 20th century — black holes are areas in space that have such strong gravity that not even light can escape them.
However, there is little known about them. We don’t even have a real picture of one.
That knowledge gap is where Rebecca Phillipson comes in. A physics graduate student in the College of Arts and Sciences, Phillipson dreams of discovering more about what makes black holes work.
Now, after being awarded the three-year Harriett G. Jenkins Graduate Fellowship by NASA, she’ll have a good shot at it. Through the $165,000 afforded to her by the fellowship, Phillipson will be able to combine the latest simulations with a treasure trove of NASA’s telescopic data to look at black holes at a depth never before achieved.
“I’m impressed by Rebecca’s initiative and imagination,” said Michael Vogeley, PhD, professor in the College of Arts and Sciences and one of Phillipson’s advisors at Drexel, along with Steve McMillan, PhD. “It is rare for a first-year graduate student to have the vision to bring together ideas from computational and observational astrophysics to attack a problem this complex.”
Here, Phillipson explains why black holes’ secrets are so hard to discover — and how she hopes to divine them.
Why is so little known about black holes and their growth? What makes it so difficult to study them?
So far, black holes can only be observed through indirect means. That is, we can only study black hole systems that are actively interacting with other objects or materials.
For example, black hole binary systems are ones in which a black hole has a very close regular star companion that feeds it matter. The matter then accretes (adds) onto the black hole and, thereby, gives off radiation that we can then detect with telescopes. Similarly, supermassive black holes at the center of galaxies, like the one in our own galaxy, will greatly affect their environments, such as the trajectories of nearby stars in their orbits.
But we cannot detect stand-alone black holes, and we have yet to image a black hole directly. Since the environments around such systems are incredibly violent, the closer you get to a black hole, the more challenging it is to discern its behavior amongst the chaos.
What makes your new work possible?
The work of previous scientists is essential and necessary for progress in studying black holes. Theoretical models can be analyzed and tested by more and more advanced simulations as technological resources expand.
Also, we now have decades of observations of black hole systems from NASA telescopes that can help us verify the theoretical models and, furthermore, investigate the long-term behavior of these systems.
The longer the data sets you can obtain, the more information you can potentially extract.
The goal of my fellowship is to combine real data analysis with computer simulation of black hole systems across the entire scale of black holes (ranging from ones the size of our sun to the supermassive one at the center of our galaxy). This essentially allows us to test current theories and our own observations against our own personal laboratory of a black hole simulation.
Why do we want to know more about black holes?
The study of active galactic nuclei — which are generally accepted to be supermassive black holes actively accreting matter — will contribute to the study of galaxy evolution, since the central black hole of a galaxy is tied to the evolution of the host galaxy as a whole.
Since active galactic nuclei are incredibly luminous objects that can be seen at great distances, they can also inform us about the intervening material between us and them.
And we desire to study black hole binaries because although they are smaller systems, we might be able to determine if there are any similarities to active galactic nuclei that may allow us to study the larger black hole systems from a different angle.
What would make your fellowship a success to you?
If, in analyzing all of the NASA telescope archives and running the simulations, we start to see a previously unexplored theme in black holes’ long-term behavior that carries across the scales from baby black holes all the way up to the supermassive ones, I would view that as a huge success.
Media interested in speaking with Phillipson should contact Frank Otto at 215.571.4244 or fmo26@drexel.edu.
