Dr. Eric Coughlin is the most recent addition to the faculty roster of our department, and already he has begun to leave his mark on our community after permanently arriving only six months ago. Beyond his research on tidal disruptions of stars by supermassive black holes, Dr. Coughlin, who prefers to be called by the less formal Eric, has assembled a large number of graduate and undergraduate students into his research group, kickstarting the next generation of Syracuse Astrophysicists. In addition to taking on the advisor role for so many, Eric has been instrumental in enriching the department colloquia, sponsoring three separate speakers from outside of Syracuse this fall semester alone. The last six months have been very active for our department’s newest faculty member, and unsurprisingly this is demonstrated by recent publications from Eric’s group on Tidal Disruption Events.
Eric first got into the field of tidal disruptions in graduate school at CU Boulder, where, as he says, “I knew I wanted to do cool and fun math.” Perhaps there is no environment quite as cool and fun for an astrophysicist as that of a supermassive black hole. Black holes are the most compact objects in the universe; they are so dense that light itself cannot escape their gravitational pull, explaining the ominous name of black hole. Supermassive black holes are truly gigantic, ranging from millions to billions of times more massive than the Sun. They are found at the centers of almost every large galaxy, and are thought to play an important role in the formation of these galaxies. Eric studies stars that stray too close to these gravitational giants and are subsequently ripped apart; this is a Tidal Disruption Event (TDE).
Eric has recently pioneered work to differentiate these disruption events from one another. After being torn apart by the black hole, the material of the star, mostly dust and hydrogen gas, gets gravitationally bound to the black hole, forming an accretion disk. As the dust and gas falls towards the black hole, it heats up and radiates light, which astronomers can detect. Eric’s models have found different accretion rates based on whether the star was completely or partially disrupted. This allows him to determine whether the star had high mass or low mass. High mass stars’ outer layers are much more loosely bound than their cores, so when they get disrupted it results in just the outer layers being ripped off; this is a partial disruption. Low mass stars’ outer layers and core are bound much more uniformly. When low mass stars get disrupted, they are completely torn apart; this is a total disruption.
Galactic centers, the environment where these supermassive black holes live, are filled with dust, stars, and stellar remnants. On large scales, they are the most dense areas of the Universe. As such, studying what is going on inside them can be very challenging. In the words of Eric, “The galactic center is an absolutely crazy place.” Once observational astronomers have compiled more observations of TDEs, he can use the scaling difference between full and partial disruptions to discern whether or not there are more high mass or low mass stars that fall victim to this disruption process. By doing so, Eric will give the astronomy community valuable insight into the nature of galactic centers just like our own all over the Universe.
Today Eric sits poised to leave his mark on both the Astrophysics community and our own department. However, his journey to this point was never so assured. Surprisingly, Eric entered Lehigh University at 18 as an engineering major. He quickly switched to astrophysics after refocusing on what he knew his passion to be, but even then Lehigh had a nascent astrophysics program. There was no guarantee he would enjoy the work to be done at Lehigh. Additionally, like many physicists and astronomers, Eric’s family was not rooted in academia. As such, he did not know what being an astrophysicist fully entailed; all the years of additional education and post-doctoral research that would come after graduating from Lehigh. Even after all those years, he would have to then do his own impactful research completely independently. Eric recalls having a conversation with his advisor, when he first learned of all this. “That was terrifying, because I don’t know what the hell I’m doing,” he said with a humorous laugh to cap it off.
Even after learning the obstacles in his path were more daunting than he could have imagined, Eric stuck with it. He always had a passion for studying space, he doesn’t remember a time when he did not want to be an astrophysicist, but this alone was not what carried Eric through to a career in astrophysics. When he was in 6th grade, his elementary school had a poster fair advertising what each student wanted to be when they grew up. Eric’s poster was about how he wanted to be an astronomer. After the event, he remembers a conversation he had with his mom, Kathleen. Eric comes from a family of stockbrokers; his dad, uncle, and grandfather were all stockbrokers. Even as a child, he could see the pattern emerging, so much so that he told his mother that being an astronomer is an interesting dream but he would probably end up being a stockbroker (a profound and insightful comment for a twelve year-old). To this day, more than two decades later, Eric remembers how his mom reacted. “She looked me in the eyes and said, ‘Eric, you can be whatever you want. You should not let what your dad did drive you to do what you want to be. You can absolutely do this.’ That was probably one of the main reasons why I stuck with it as long as I did and why I am here today.”
Stick with it he did. In the months leading up to his graduation from Lehigh, Eric earned a spot at CU Boulder in the astrophysics department and had planned a trip to visit. His trip was almost quashed by a flat tire on the way to the airport, but thankfully his friend who was driving him had parents who lived in the area and got him to the plane as it was taking off. Had he missed that flight, Eric would have probably gone to Cornell and his life path would look completely different. Thankfully, he made the flight, and it was at Boulder as a graduate student that he first started researching tidal disruptions.
While he was solving problems involving the myriad assortment of objects flying around galactic centers, there was another problem Eric was solving; the infamous two-body problem that plagues graduate students and academic professionals the world over. While Eric was earning a PhD in Boulder, a process that would eventually take five years, his high school sweetheart and future wife, Sarah, was in Pennsylvania getting a degree in physical therapy. For the first two years of his PhD, they were separated by a distance only manageable via plane. “That was tough,” Eric remembers. Luckily for him, after two years Sarah had a very valuable degree in physical therapy, and could get hired pretty much anywhere in the country. Once she finished her degree, she joined him at Boulder. Perhaps Sarah deserves most of the credit for solving the two-body problem for this academic professional.
After graduating from Boulder, Eric earned an Einstein fellowship and brought it to UC Berkeley for his first post-doctoral position. It was here where he and his wife had their first child, Josephine, and began the lifelong occupation of being parents. Eric and his family lasted almost two years in California before he shifted to a post-doc position at Columbia and subsequently Princeton. All the while, Sarah was finding physical therapy jobs in the cities they needed to move to, a process that could certainly not be described as easy. After these transitory years, Eric was hired as faculty at Syracuse University.
Since arriving in Syracuse, Eric has been busy thinking about or actively pursuing his goals for himself and the department. Eric arrived believing that he would start out slow with advising. Instead “it kind of went from 0 to 100 real fast,” he remarks on his four graduate and one undergraduate students. Eric wants to be the best academic advisor he can be, and balancing that can be nerve-wracking. In addition to the academic responsibilities, he also is working to secure funding for his students. “It’s a lot going on. A lot financially I am trying to keep aware of,” he remarked. He is already off to a solid start, as he has recently secured an NSF grant to do TDE research.
The teaching does not end with just his research group, as Eric is also preparing to lead his own classes in the Spring. Although he has expressed being nervous for his first classroom teaching position, a class titled Intro to Stellar and Interstellar Astrophysics, it is also a large source of exci
tement. Eric plans to mould this class into something new; his students will not only learn about stellar evolution, but also the stellar graveyard of white dwarfs, neutron stars, and black holes that are left behind after a star stops burning hydrogen. His love for all things space will certainly bleed into the lectures, and make virtual learning much more palatable.
In addition to the required responsibilities of advising, teaching, and research, Eric has also taken up additional work to benefit the department. He has started by getting involved in the graduate student admission committee. “I’m on the committee for that [graduate student admissions] and so I’m really interested in seeing how that whole process works and being able to take a more holistic approach to the properties of the students they [Syracuse Physics] have coming in.” There are few positions that so directly impact the future of the department, and Eric hopes to leverage that position to bring great change to Syracuse Physics.
A further change in the department that Eric is currently brainstorming is the creation of an Astronomy or Astrophysics major. This undertaking would require new classes to be offered, and qualified faculty to teach those classes. Even with these obstacles, the interest in the student body is certainly there, and Eric does not want to see that enthusiasm go to waste. On a smaller scale, he has also thought about creating a new graduate level physics course on Astrophysical Fluid Dynamics. Eric wants the Syracuse Physics Department of the future to be better for its students than that of today, and is actively working to make that dream a reality.
Eric has already been a great addition to the faculty of the department, even with only half a year of work under his belt. While reflecting on his path to get here, he had these introspective words, “If someone had told me [in undergrad] it was going to be however many years, I guess almost 10 years after finishing undergrad, that I would be able to have a permanent job, I don’t know if I would have done it. I am extremely happy that I followed through.” Astrophysics is Eric’s passion, and it was worth the sacrifices to pursue that passion. Our department is lucky to have someone who will bring that passion to the classroom, to his research group, and to the department as a whole every day.