Dr. Kelly Whalen (she/her/hers)

Extragalactic Astrophysicist
X-ray Astrophysics Laboratory (662)

What science questions do you investigate?

I am primarily interested in understanding how galaxies and their central black holes form and co-evolve with each other. At the center of every massive galaxy is a supermassive black hole. These black holes can range from having masses of ~a million-a billion times the mass of the sun. Observations of large samples of galaxies show that there is a tight relationship between the mass of a galaxy and the mass of its central supermassive black hole, suggesting that they might evolve with each other; although the mechanism by which that happens is unknown. Supermassive black holes grow mainly by feeding on gas in the center of their host galaxies, and galaxies grow in stellar mass when gas is cold and dense enough to collapse into stars. One way of regulating the growth of both supermassive black holes and galaxies is by disrupting gas, either by heating it or ejecting it altogether. Both, the ongoing growth of supermassive black holes and the deaths of massive stars can be capable of injecting energy into gas and galaxies, disrupting future black hole growth and star formation. I study galaxies that are experiencing extreme bursts of star formation and black hole growth to understand how important these forms of energy injection, or feedback, are in shaping the populations of galaxies and black holes we observe throughout cosmic time.

Did you always know that you wanted to study astrophysics?

To a degree, I have always had an idea. I was obsessed with space as a kid. If you asked me as an elementary schooler, I would have told you I wanted to be an astronaut or an astronomer when I grew up. As I got older and exposed to more in science, I also began to enjoy physics and chemistry. However, I realized I was serious about astrophysics during my time as an undergraduate. I decided to major in physics since I felt I could pivot towards either astrophysics or chemistry once I had a better idea of what excites me the most. During my freshman year, my introductory physics professor invited me to join her research group that focused on the evolution of galaxies in clusters, and I fell in love with the science. I then went on to explore some other fields in astronomy such as planetary science during an NSF Research Experience for Undergraduates, but nothing quite grabbed me like galaxy evolution. As a grad student, I joined a research group focused on galaxies and growing black holes, and that has become my area of focus since.

I have had dreams of working at NASA since I was six years old. Although I'm no longer actively trying to travel to space as I was in this picture, I still spend most of my time thinking about the cosmos and the processes that have made them what they are today.
Credit: Eileen Whalen

How did you end up working at NASA Goddard?

Working at NASA was a childhood dream of mine. When I was finishing my PhD, I was applying to as many relevant postdoc positions as possible off the American Astronomical Society job register. One advertised position was for the NASA Postdoctoral Program fellowship. It sounded like a perfect opportunity for me, as it was focused on the co-evolution of highly star forming galaxies and their central black holes. I reached out to Dr. Kim Weaver to ask about the advertised job and to discuss possible project ideas. I ended up applying for the fellowship, and I was fortunate enough to be selected!

What is one research project that you are particularly excited about, and why?

I've recently been excited by my work focusing on objects referred to as “Little Red Dots.” Little red dots are objects that have been observed in deep JWST images that completely challenge our current understanding on how galaxies and black holes grow, mainly because there's not yet a consensus of what they are! They are either the first galaxies or the first supermassive black holes to have formed in the universe, but there is open debate as to which they are. They exhibit some properties that are consistent with them being growing black holes, such having small angular sizes and strong, broad emission lines in their spectra. However, they also lack typical signatures of growing black holes such as X-ray emission. Some of my current work is focusing on understanding the limitations of the tools we use to measure the physical sizes of little red dots, which will help us put constraints on whether or not they are too small to be galaxies within the capabilities of our analyses.

JWST images of the mysterious little red dots. One current focus of mine is trying to determine whether the light from these objects is from starlight in galaxies, growing supermassive black holes, or a combination of both.
Credit: Matthee et al. 2024.

What aspect of your work are you most passionate about?

I love being able to share my work with others! In an academic sense, I enjoy going to conferences and being able to discuss my work with other scientists working in my field. I always feel inspired upon returning from a conference having just spent the week exchanging ideas with others and forging new scientific connections. In a broader sense, my favorite people to share my work with are members of the public. I've done outreach events with schools, museums, and local observatories, and there is nothing more fun than fielding the wonderful astronomy questions that some curious attendees have been stewing over the whole event. Even just chatting with strangers I meet out and about in the world is incredibly rewarding. If a five-minute conversation about the cosmos is enough to pique someone's interest in science as a whole for the first time, it was a five-minute block of time well-spent.

One aspect of my work that I love is being able to share ideas and collaborate with other scientists. Conferences can act as a great meeting point to either network with new colleagues or to reconnect with long time collaborators. This is the conference photo taken at a recent Massive Black Holes in the Early Universe meeting I attended in Kinsale, Ireland.
Credit: Michael Tremmel.

What early career advice do you have for those looking to do what you do?

My biggest piece of advice would be to seek out good mentors who demonstrate a desire to elevate the students they work with and who care about their students' success. From Dr. Rose Finn at Siena College, to Dr. Ryan Hickox at Dartmouth College, to Dr. Kim Weaver here at NASA Goddard, I have been very fortunate to work with some amazing mentors throughout my career. I largely attribute any success I may have had so far to the opportunities presented to me by people who are not only good scientists, but who also care about their advisees as people and who want to see them succeed. This has ranged from being supported by advisors to present at conferences early in my undergraduate degree, to more recently being introduced to collogues of theirs who have since become collaborators of mine, to actively helping me learn new skills to expand my ability to conduct new aspects of research. They have inspired me as a scientist, and they have helped shape my ideas as to what a mentor should be as I move along in my career and eventually advise students of my own. Finding a good mentor is incredibly special and is something that can go a long way with shaping your professional network and opening doors throughout your career.

What do you like to do in your free time?

I love to be outside! My favorite hobby is downhill skiing, even though I don't get the chance to do it as much since moving to the DC area. I also spend a lot of time running and hiking. I found a local running group in DC that has shown me new routes, and I've gotten the chance to explore nearby trails in MD and VA. I'm also a huge music fan; when I'm not enjoying the outdoors, you can find me listening to my favorite bands live at venues across the DMV.

My favorite hobby is downhill skiing. Living in New Hampshire for graduate school allowed me to explore many of New England's ski areas. This was taken at Okemo in Ludlow, VT.
Credit: Greg Casto.