By Anna Ferraro
Photos/Special to The Source Newspaper
Update: Riley Dunnagan is part of a group officially publishing a paper this year. She has accepted a summer research position at the Green Bank Observatory in Green Bank, West Virginia, working on radio astronomy data. She has recently become president of the Rose-Hulman Astronomical Society.
“It’s a big universe out there, and finding its secrets is, in my opinion, a noble cause,” said Riley Dunnagan, a graduate of Routt Catholic High School (RCHS) who is making her mark in the world of astrophysics. Currently a junior at Rose-Hulman Institute of Technology, Dunnagan made some significant academic advances in early 2019 that lead to her being asked to present to the American Astronomical Society in Seattle. While the initial hype surrounding her research was spun around her “discovering a black hole,” Dunnagan stepped in quickly to add comments and clarification. In sharing these with The Source, we now excitedly share them with you, our reader, and hope, as Dunnagan expressed, that you would be inspired to learn more about God’s amazing universe yourself.
Before we start talking about astrophysics, let’s get to know Dunnagan a little bit. Growing up primarily within the Jacksonville area, she landed at Our Saviour School in seventh grade and then Routt Catholic High School, where she finished out her secondary education. Looking back on her years at RCHS, Dunnagan shared, “A significant amount of credit should go to Mr. Scott Maruna, the physics (among other subjects) teacher at Routt. He was the first to encourage me to look more into research and academia, and he really helped foster my love for physics.”
Her teachers at RCHS were not the only influential individuals shaping her heart and mind, though. She shared, “Both of my parents (Angela and Richard Dunnagan) have been extremely supportive in my exploration of science and engineering; I have fond memories of my father, an amateur astronomer, showing us the moon through his telescope when I was little and telling me that I would work at the W.M. Keck Observatory in Hawaii. I denied it, adamant that I was going to be a geologist and study volcanoes. Turns out, he was right in the end. My mother was the one who strongly encouraged me to attend university at Rose-Hulman – we went on a college visit in the winter of my senior year of high school and immediately upon meeting my host for the weekend, I knew that she was right, that these were my people.”
But astronomy and astrophysics are hard. So, how does even a motivated student with good teachers and inspiring parents become so enraptured with such topics to devote her life to them? Dunnagan’s answer was clear. She stated, “I remember looking at the moon one night coming back from a swim meet and suddenly realizing the scale of our solar system … how massive the moon must be, and how far away it would have to be in order to diminish the size from our perspective. It felt like an awakening of sorts – how truly fortunate we must be to see something so beautiful and regard it as mundane and ordinary … ever since, I have wanted to know more about our galaxy and the universe beyond.”
Upon graduating from RCHS in the class of 2016, Dunnagan headed off to Rose-Hulman Institute of Technology in Terre Haute, Indiana. Her collegiate career progressed smoothly as she narrowed in on an undergraduate degree that would nurture her love for astronomy and astrophysics. And then, as social media reported in early 2019, she suddenly “discovered a black hole.” Well, almost … so, with that, we’re going to step aside from our commentary, and let Dunnagan speak for herself on this.
Dunnagan said, “I would like to clarify, first and foremost, that my research was primarily diagnostic in nature. To begin, I will explain in detail what exactly happened. For the laymen, as a review from physical science, light comes in a spectrum of wavelengths/frequencies. We see light mostly in the visual spectrum, which is a narrow band of wavelengths that our eye can process. I have been focusing more on the radio spectrum of light, which is longer wavelengths than infrared and microwaves – in fact, most of the data that we send back and forth is in radio! All of your television broadcasts, the data from your phone, airplane communications, etc. are light waves sent in this low frequency/long wavelength light. What is nice about radio light is that it can be seen whereas higher frequency light, like visible light or x-rays, would be obscured by dust in the way.”
“Now, N3 was discovered long before my research began as an interesting spot in the neighborhood of the center of the galaxy in the middle of what astronomers call the ‘Radio Arc.’” The Radio Arc is a non-thermal band rather close to Sagittarius A, the supermassive black hole at the center of our galaxy. It has long been a mystery why the Radio Arc is so bright, compared to other filaments around the galactic center.
“There was some speculation that N3, this very small and very bright radio source, could be contributing to the brightness of the Radio Arc, which is why more research has been done on it … Under supervision of [my advisor] Dr. Ludovici, my research partner Katana College (mechanical engineering major, class of 2021) and I had two tasks at hand: determine whether or not N3 is variable, or changes brightness, over the short timescale of a couple of months, and look further of the molecular composition of the cloud in front of N3.”
“We were able to conduct such research due to use of the Karl J. Janksy Very Large Array (VLA), funded by the National Science Foundation. This telescope is a collection of 28 radio dishes all pointed at the same point in the sky, much like you would find on top of a house receiving television stations (except much bigger – each dish is 25 meters in diameter). While bright, N3 is still relatively a very dim object to us, which is why the telescopes generally have to be so big. If you were to place your cell phone on the moon, it would be the third brightest radio object in the sky!”
“The most exciting discoveries came from analyzing the data from the molecular cloud in front of N3. We discovered three different types of molecules – methanol, which we expected to see based on past observations; formaldehyde; and HC3N. We see methanol a lot on earth, but you might not expect to see the last two in space. A combination of cold temperatures and very low gravity make it so that exotic chemicals you would not find on earth are abundant in space. The formaldehyde detection was significant because, through its position in the cloud, it meant that N3 most likely lies somewhere between the back of the cloud and the edge of the observable universe, which was contrary to our working hypothesis of N3 being embedded in the cloud.”
“The HC3N detection wasn’t remarkable in and of itself, but because it was detected in such a narrow strip of the cloud, it is backlit by N3, and it is of a particular quantum mechanical state, it became a rare find. In fact, this was one of the most important and exciting findings, as this particular chemical in this particular state has only been seen once before in the galaxy (Hunt et al. 1999). While the cloud is pretty small (about 2*1013 miles across, which is very small on an interstellar scale), this discovery helped point toward the approximate density of the cloud – which is remarkably dense for its size. This data proves significant for the collaborators on this research project and will be included in a paper in preparation led by Dr. Natalie Butterfield of the National Radio Astronomy Observatory.
“As for N3 itself, my advisor presented two initial hypotheses: that N3 was a small black hole, comparable to the size of the sun, that was in such a unique orientation that has never been observed before, or that it was what we call an Active Galactic Nucleus (AGN) – a supermassive black hole of another, much more distant galaxy. We looked at how N3’s brightness changed over time. Based on previous observations, we knew that N3 changed brightness over the time scale of years, but in order for it to be a small black hole within our galaxy, it also needed to change significantly over the scale of a month or two. Our observations and analysis concluded that N3 is likely not variable over the span of a couple of months, leading us to believe it is probably an AGN. The analysis hasn’t officially concluded, as the paper is still in preparation and there are a few other aspects that we can/need to investigate, but that is where the diagnosis rests for now.”
As she concluded her astrophysics explanations, Dunnagan summarized and explained, “Science is never an individual effort – it is always a collaboration, built on top of the works of others.”
In January of 2019, Dunnagan presented her ideas and findings at the American Astronomical Society (AAS) in Seattle, WA. She reports, “My presentation [and trip] was very successful … I received a lot of helpful and insightful feedback from amateur astronomers to other undergraduates to the postdoctoral advisor of my advisor’s doctoral advisor. I learned an incredible amount through this research and through the experience of presenting at the AAS conference and am very grateful for the travel grants I received in order to go.”
With a huge accomplishment like this under her belt, Dunnagan’s school year continued on – with full days of coursework and a healthy extracurricular load, as well, including being involved in the Rose Drama Club on campus as well as a member of the Model European Union team, Dunnagan’s spare minutes are gone.
Looking ahead, she shared, “I plan on going to graduate school and obtaining a Ph.D. in either physics or astronomy. Whether or not I go into industry first is up in the air – I try not to limit my choices – but that’s what I am working towards. I would eventually like to teach at the university level, maybe even returning to Rose as a professor of astronomy and carrying on the torch like other alumni have done.”
In closing, Dunnagan stated, “I appreciate all the time, energy and dedication my teachers have poured into my education. Without their long hours and their encouragement, I doubt I would be where I am today. I also appreciate the opportunity to share my discoveries with the audience of The Source and hope that, while my findings aren’t as cool as discovering a black hole per se, you enjoy (and maybe learn something from) the research I’ve done.”