Meet the DAWN-IRES Scholars: Emilie Burnham

Banner photograph by Emilie Burnham of the DR Byen neighborhood, a modern urban district along the M1 metro line on the island of Amager, south of central Copenhagen, visited during her time at DAWN.

Tell me a little about yourself. I'm finishing my third year as a PhD student at Penn State, where I work with Joel Leja studying galaxy formation and evolution. I have a deep passion for building software and working with data science, and I try to interweave that with the science itself, which tends to focus on star formation in distant galaxies. I did my undergraduate degree at Texas Christian University in Fort Worth, Texas.
My dad was in the military, so I grew up all over the US — born in Arizona, lived in upstate New York near the Canadian border, Hawaii, and various places in Texas, which is where I spent the most time. I don't really identify as being from any one place. I'm just American.

Outside of research, I love to read, particularly books that are too large to fit in a bag, which is why my Kindle has been essential for this trip. I also write my own things, whether more philosophical or fiction. And I love to cook. My approach is to make a new recipe every week and embrace anything complicated; I made an entire Thanksgiving dinner by myself a couple of years ago. My favorite thing to make is risotto.

How did you get interested in astronomy? As a kid, I was obsessed with Nova documentaries. I would watch them secretly, under the covers at night. But I always assumed I wasn't smart enough to actually pursue it. I didn't seriously consider astronomy as a career until college, when I started out in physics and just naturally got funneled toward it. It felt like a complete accident.

What kept me going, and still keeps me going, is that astronomy feels like a pure science. It's curiosity for curiosity's sake, with no obvious practical application driving it, and I find that philosophically very fulfilling. It's also remarkably collaborative compared to many other fields.

What is your favorite part about Copenhagen? DAWN? What I've loved most about Copenhagen is the culture and the people. I've had so many good conversations here, the kind I hadn't had in a long time, with such a wide range of people. The city itself rewards that kind of connection in a way I didn't expect. I also discovered, somewhat by accident, that being in a city is really good for me. I hadn't known that before coming here. It's something I'm now actively thinking about as I look toward future positions.

At DAWN, what strikes me most is how complementary everyone's research is. Here, everyone is interested in the physics of galaxies in the early universe, so research that would be quite niche anywhere else suddenly has a whole room full of people who are genuinely engaged with it. People are focused on their own work but still deeply collaborative and willing to brainstorm, to help, and to forge new connections across projects. That's a rare environment.

What motivated you to apply to an international summer research program? Honestly, I wanted to apply to something competitive for the practice, and if I got in, it would be a great networking opportunity. Since a large part of what I work on is building software, I was particularly motivated by the chance to be around the people who would eventually use that software. Being embedded in that community, hearing what they actually need, was a real draw. I didn't realize until I arrived in Copenhagen how much I thrive in that kind of environment.

Can you tell us about your work this summer? I've been working on two connected projects during my time at DAWN.

The first concerns how we study star formation in early galaxies. In the early universe, star formation in galaxies is thought to be "bursty": galaxies cycle through intense bursts of star formation followed by quiet phases. But when astronomers plan follow-up spectroscopic observations, we naturally tend to target the galaxies that are bright and active (i.e., the ones in a burst). This means the galaxies in a quiet phase get systematically missed. My research concerns understanding how much this selection bias distorts our picture of how bursty these populations really are. Early results suggest that if you don't account carefully for your selection process, you end up thinking that star formation in distant galaxies is much smoother and more uniform than reality, which is consistent with what others in the field have been finding.

The second project is building a new spectral energy distribution (SED) fitting code. SED fitting is a technique for modeling the light emitted by a galaxy across many wavelengths to infer its physical properties, such as how many stars it has, how quickly it's forming new ones, what it's made of. My code uses neural network emulators to do this much faster than conventional approaches, making it possible to fit very large populations of galaxy spectra from next-generation surveys like PFS, MOONS, and DESI. This summer has been focused on developing a robust inference pipeline that produces well-calibrated results. It's still in progress, but it's the kind of tool that the community genuinely needs, and I've had plenty of conversations here at DAWN about exactly how and why.

What skills have you been working on developing this summer? As a Senior Scholar, a big part of my role has been mentoring the undergraduate students, including asking questions about their research, offering outside perspectives, helping them think through problems rather than just giving them answers. That kind of mentorship is a skill in itself, and I've been thinking a lot about pedagogy: what does someone who has never done research before actually need to know, and how do you teach it well?

I've also been working on scientific communication, including how to tailor a talk or a conversation to a specific audience, figuring out what they're curious about, and leaving room for the kinds of questions that can turn into future collaborations.

And as someone who comes from the modeling and simulation side of things, I've been stretching myself to think more like an observer. How does an observer actually plan a survey? What decisions are being made and why? That perspective is hard to develop without being surrounded by people who live it, which is part of why being at DAWN has been so valuable.

What Danish word or phrase have you picked up? I'll be honest, I haven't picked up much Danish. My defaults are hej (hello) and tak (thank you), and that's about it. What I have picked up are Europeanisms. I now say "the bin" instead of "the trash" and "the shop” instead of "the grocery store.”

But the thing I'm genuinely bringing home from Denmark is the breakfast. My favorite is a bun and cheese with a filter coffee! I'm not normally a breakfast person, so this is a big deal.

You can learn more about Emilie’s ongoing research by visiting her professional webpage at https://efburnham.github.io

Meet the DAWN-IRES Scholars: Lucas Zimmermann

Banner photograph by Lucas Zimmermann of the beach at Møns Klint, a coastal area south of Copenhagen, during a weekend trip with fellow scholars.

Lucas Zimmermann at the top of Kattanakken in Jostedalsbreen National Park, Norway, during a week-long campervan trip with fellow scholars. Photo by Mahitha Ramachandran.

Tell me a little about yourself. I'm a rising senior at Yale University majoring in astrophysics, and I'm also getting a certificate in data science. This includes courses on statistics, probability and machine learning, which compliment astronomy research very well.

Outside of class, I co-founded the Yale Astronomical and Space Student Society in my sophomore year and have been co-president since. Being able to bring astronomy to those outside the field is very fulfilling. I'm also on Yale's club cycling team, where I race and serve as race coordinator. We compete all over the Northeast, including New York, Connecticut, and Pennsylvania.

How did you get interested in astronomy? I've been interested in astronomy since I was very young — it just stuck. Growing up in Brooklyn, I couldn't see much of the night sky, but I loved learning about it. In middle school I joined the Amateur Astronomers Association of New York, which offered classes I could take to go deeper and help solidify my passion.

My high school, Brooklyn Tech, has an unusual system where you pick a major after two years, which determines your electives. I chose physics, partly because it included an astronomy course that allowed me to learn more.

The summer before my senior year, I spent two months at Yale doing astronomy research through YSPA, the Yale Summer Program in Astrophysics, working with a cohort of about 36 students on near-Earth asteroids. We used telescopes to track how asteroids moved across the sky and modeled their orbits from our observations. That experience was a big reason Yale became my top choice and was my first introduction to doing research. At that point it felt less like a decision and more like the obvious next step.

What is your favorite part about Copenhagen? DAWN? As someone who races bikes, the cycling infrastructure here is genuinely remarkable. I came in with an appreciation for it, and Copenhagen has exceeded every expectation. I rented a commuter bike for getting around, but the local coordinator of the DAWN-IRES program, Peter Laursen, also lent me his road bike for longer rides. I've biked around Amager on the southern end of the city, explored a hillier lake area in the north on a route Peter suggested, and, the highlight, did a century ride with fellow scholar Alexander Poulin, all the way to the northern tip of Zealand, the island Copenhagen sits on.

At DAWN, what stood out most is the cohort. We've traveled together, hung out together, and shared a lot of new experiences. There's also the research culture here, which surprised me — it's much more relaxed than what I'm used to in the US, with people coming in later and leaving earlier. But the amount and quality of research being done is genuinely impressive, and it's a wonderful environment to be part of.

What motivated you to apply to an international summer research program? I love doing research and I love traveling, and this was a chance to combine both. Last summer I spent the time doing research in Santiago, Chile, which was its own incredible experience, and I was excited to try something completely different. I have family in Germany and I've traveled widely in Europe and was happy to have a reason to be here for an extended time. In fact, after the program, I'm heading to Berlin.

Can you tell me about your summer research project? I'm working with Yi Xu and Koki Kakiichi to search for Population III stars, which are the very first stars that ever formed in the universe. These stars are thought to have formed from purely primordial gas containing only hydrogen and helium, with none of the heavier elements that later generations of stars produce. No one has ever directly detected a Population III star, and finding evidence of them is one of the outstanding goals of modern astronomy.

My approach is to search in the outskirts of massive galaxies when the early universe was roughly 700 million to one billion years old. The idea is that small pockets of gas near these massive galaxies may stay metal-free for longer, kept pristine by radiation from the galaxy next door, making them more likely to host Population III star formation.

I'm working with existing IFU data, which are observations taken with instruments that capture a spectrum at every point in the field of view, not just a single spectrum or a single image. The surveys were originally designed to study the massive galaxies themselves, but I'm searching their outskirts for candidates. The signature I'm looking for is a detection of hydrogen emission with no metal lines. That absence is the tell, as it suggests the gas is still primordial. I can't say definitively that any individual object is a Population III star, but I can use my detection limits and candidate counts to constrain theoretical predictions for how many such stars should exist in the volume of sky I've searched.

What skills or knowledge have you been working on developing so far this summer? Working with spectra has been the main new skill. I hadn't done much of it in a real research context before, such as measuring the brightness of an emission line, subtracting the background, and fitting a mathematical curve to an emission feature to measure its strength precisely. And then, practically, how you pull individual spectra out of a three-dimensional IFU data cube. These are skills that can take a while to build, but having a project that required all of them has pushed me to develop them relatively fast.

What Danish word or phrase have you picked up that you now use constantly? Skink — the word for ham, which is the same in Danish and Norwegian. I learned it on a campervan trip to Norway with fellow scholars Alex and Mahitha. We rented a van in Sweden, drove up through Norway, hiked mountains, and ate a lot of sandwiches. Ham was a staple, so every time we went to a grocery store we were on the hunt for skink. We thought it sounded funny, and it became a running joke for the whole trip.

Meet the DAWN-IRES Scholars: Alexander Poulin

Banner photograph of the beach at Tisvilde, a small coastal town on the northern tip of Zealand, taken at roughly mile 60 of Alexander’s 100-mile bike ride.

Picture of Alexander Poulin at the beach of Tisvilde, one of the destinations along his 100 mile bike ride, taken by fellow scholar Lucas Zimmerman.

Tell me a little about yourself. I’m a rising senior at Northeastern University in Boston, majoring in computer science and physics with a minor in astrophysics. At Northeastern, I’ve had the chance to explore a lot of different areas of physics research, including particle physics at CERN, condensed matter, and more recently astrophysics. I grew up in Sudbury, Massachusetts, so I’m not too far from home.

Outside of research, I enjoy cooking and baking, my favorite things to make are cinnamon rolls and croissants. I take film photographs and develop and scan them myself. I’ve played ice hockey pretty much my whole life, starting when I was about four. I also played baseball and soccer growing up, but hockey was always my number one passion. I’ve tried to keep it going in college through intramurals, though Northeastern’s rink was recently torn down, so we’ve been without one this past year.

How did you get interested in astronomy? Growing up, I watched a lot of VSauce, a YouTube channel that makes STEM content entertaining. They covered a wide range of stem topics including astronomy, which got me thinking about it. But things clicked more concretely in high school, when I did research at STAR Laboratories (Speech Technology and Applied Research) in Lexington, Massachusetts. My mentor there had studied astrophysics and sometimes our conversations would evolve into astronomy topics. Many of the signal processing techniques used in speech research carry over directly to astronomy, and that connection made me see how I could combine my interest in computer science with physics, and eventually land in astrophysics.

What is your favorite part about Copenhagen? DAWN? The biking culture has been incredible. Before coming here, I genuinely hadn’t ridden a bike since I was about 12, so I was pretty rusty at first. Now I bike everywhere, to NBI and even all the way out to DTU, which is 12 miles one way. One of my favorite moments during the program so far has been biking over 100 miles in a single day with a fellow scholar and friend, Lucas Zimmermann, all the way to the northern tip of Zealand (the island the majority of Copenhagen sits on) to Gilleleje and Tisvilde.

At DAWN, what stands out is having a large group of people all working on astronomy. At Northeastern, there are only a handful of astronomy faculty, and research tends to happen in fairly isolated lab settings. DAWN feels much more collaborative; people are genuinely willing to help each other, and there isn’t the kind of hierarchy you might expect to find.

What motivated you to apply to an international summer research program? I hadn’t traveled much before this. I’d only been outside the East Coast once. This felt like a real opportunity to actually immerse myself in another culture for an extended period rather than just visiting. I also have graduate school applications coming up and wanted to get a sense of what the culture in Europe is like, and what science and doing research in Europe might be like.

Can you tell me about your summer research project? I’m working with Shuowen Jin and Marko Shuntov on a search for unusual objects in COSMOS-Web, a wide-area survey conducted by the James Webb Space Telescope (JWST).

Specifically, I’m looking for objects that are invisible at shorter near-infrared wavelengths but suddenly appear bright at longer ones, which we call “F277W dropouts”. Exactly what these dropout objects are, their properties, and their origins, is still unclear. They could be distant star-forming galaxies, stars in our own Milky Way, distant massive black holes, or the mysterious compact objects known as “Little Red Dots” that JWST has been uncovering.

We found 29 such dropout objects in total. Without spectral data, which measures light intensity by wavelength, we’ve had to rely entirely on JWST photometry and radio data from ALMA, MeerKAT, and the VLA to characterize the objects by modeling their light across multiple wavelengths, a technique called spectral energy distribution (SED) fitting. Some of the objects were large dusty galaxies resulting in relatively straightforward SED fitting, while others were far more compact, requiring that we stacked their images together to analyze their combined light. Even still it’s hard to say definitively what they are, and that’s still what we’re working toward.

What skills or knowledge have you been working on developing so far this summer? My previous research has been mostly simulation-based, so observational work has been the big new frontier, including learning to work with telescope images, run statistical analyses on real data, and account for how the specifics of each instrument affect what we actually measure. SED fitting was entirely new to me as well.

More broadly, I’ve been developing independence as a researcher. This project is genuinely open-ended: my mentors and I are both trying to figure out the same problem. That back-and-forth, where nobody already knows the answer, is what research actually feels like, and learning to navigate that has been one of the most valuable parts of the summer.

What Danish word or phrase have you picked up that you now use constantly? Tillykke med fødselsdagen — happy birthday. In June, I convinced a few of the other scholars to join me at Peter Laursen’s boxing class. We found out ahead of time that it was his birthday, and we tracked down his personal website, which has a recipes page. One of the recipes was his own rhubarb white chocolate cake. We decided to bake it for him, which, while it did not go well, hopefully showed our appreciation for the help and work he has done for us. We scrapped the whole thing and got him baked goods instead. But after the boxing class, we wished him a happy birthday in Danish, which he seemed genuinely touched by.