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.

Meet the DAWN-IRES Scholars: Maya Berhane

Banner photograph by Maya Berhane of the waterfront view from the Louisiana Museum of Modern Art in Humlebæk, Denmark.

Maya Berhane at the Museo Galileo in Florence, Italy, in front of an armillary sphere — a historic instrument once used to model the motions of celestial bodies. Maya visited during her vacation week mid-program.

Tell me a little about yourself.  I'm a rising senior at the University of Washington, where I double major in physics and astronomy, with a minor in American ethnic studies. The minor started organically — I was taking those classes because they interested me, and at some point figured I might as well formalize it. I once had bigger plans, including a second minor in applied mathematics, but I had to be realistic.

I was born and raised in the Pacific Northwest, in Washington State. My parents are both immigrants from Eritrea, a small country in East Africa near the Horn of Africa, bordering Ethiopia. My dad came to the US when he was 16; my mom first emigrated to Britain and then came here, where she was introduced to my dad through my aunt. Outside of research, I've read every day since I was about 10 — I find real comfort in it, especially now that I'm staring at a screen all day. I also journal, draw, and did karate for over a decade.

How did you get interested in astronomy?  When I was a kid, I spent a lot of time staring out the window wondering what was up there. I'd ask my dad questions — he's an electrical engineer — and we'd sit down and watch YouTube videos together about whatever I was curious about. I remember watching a video about string theory around age 10 and having absolutely no idea what I was seeing. But that was it. I've known I wanted to do astrophysics since then.

When I got to college, I quickly discovered that modern astronomy means a lot of coding. My childhood fantasy had involved peering through a telescope; the reality is more like writing scripts and staring at data. But I've come around. Coding is a tool that helps you better understand the universe — and there are scientific plots out there that are genuinely beautiful.

What is your favorite part about Copenhagen? DAWN? The biking infrastructure is remarkable, genuinely better than anything I've experienced in the US. Seattle, where I'm from, is so hilly that biking isn't really practical most of the time, so being somewhere flat with dedicated bike lanes everywhere has been a revelation. Danes also take their traffic rules seriously. I jaywalked on my first day and got some very pointed looks. I've since seen a local on a bike yell at tourists for riding slowly on the left side of the path — the left is for passing only.

At DAWN, what I love most is that it's a hub for extragalactic astronomy — the study of galaxies beyond our own Milky Way — which is exactly what I want to pursue for my PhD. Everyone here is working on something I find genuinely interesting, and there are talks every week. It's an environment where I can always find someone to learn from.

What motivated you to apply to an international summer research program? At UW, I'm a resident advisor, which comes with a contract that makes studying abroad really complicated to arrange. This summer was essentially my window. I'd also never been to Europe before, and I was curious about what it would be like to work with scientists from outside the US and experience research in a different setting. I'm really glad I came — I've even thought about working at DAWN someday.

Can you tell me about your summer research project? I'm working with Ugnė Dudzevičiūtė and Pablo Araya-Araya at DAWN/DTU on dusty star-forming galaxies — galaxies that are forming stars at an extraordinary rate, but whose visible light is heavily obscured by dust, making them difficult to detect in ordinary optical images. We're approaching the problem from two sides: what we observe, and what theoretical models predict.

On the observational side, I'm working with galaxies from the AS2UDS survey, which used ALMA (the Atacama Large Millimeter/submillimeter Array) to detect these galaxies through their dust emission at millimeter wavelengths. On the theoretical side, I'm drawing on two galaxy formation simulations: L-Galaxies, which uses simplified rules to track how galaxies grow and evolve, and Illustris, which models the physics of gas, stars, and dark matter in full detail.

My task is to find counterparts for each observed galaxy within the simulations — matching them by brightness and distance — and then compare their physical properties: how much dust they contain, how fast they are forming stars, and how those properties evolved over time. The dust modeling in simulations is tricky; dust tends to be added after the fact rather than tracked from the start, which created some complications. But I've worked through the matching phase and am now building star formation histories to see what the simulations can and can't reproduce.

What skills or knowledge have you been working on developing so far this summer? Cleaner, more intentional coding. I can code — but I've had a habit of hard-coding values directly into my scripts rather than writing flexible, reusable functions. That bit me a few times; there was a three-day bug that turned out to be nothing more than me overwriting my own variable. I'm trying to be more organized and deliberate about how I write code so it's easier to read, reuse, and debug later.

What Danish word or phrase have you picked up that you now use constantly?  Tak — thank you. I feel guilty walking up to Danish people and immediately launching into English, so saying at least one word in their language makes me feel a little better. I'm also on a Duolingo family plan with another scholar in the program, which has been fun, though the app hasn't exactly made me fluent. My goal before the summer ends is to say something other than tak to an actual person — Danish pronunciation is intimidating enough that I'm not making any promises.

Meet the DAWN-IRES Scholars: Mahitha Ramachandran

Banner photograph by Mahitha Ramachandran of the Cisternerne, a former water reservoir turned underground art space in Frederiksberg, Copenhagen.

Meet the DAWN-IRES Scholars: Mahitha Ramachandran

Mahitha standing in front of the white cliffs at Møns Klint. Photo taken by cohort member Alexander Poulin.

Tell me a little about yourself.  I'm an undergraduate at Yale University going into my senior year, majoring in Astrophysics and South Asian Studies — two very different things, but I think they represent the breadth of my interests well. I did my first year at the University of Pittsburgh before transferring to Yale.

Outside of astronomy I am particularly interested in art and art history, especially in relation to South Asia. I make my own art as well. I weave on a floor loom, make ceramics and jewelry, embroider, and sew, and I'm constantly exploring new mediums. I also play piano and have done some music production. This past year, I turned astronomical images from the James Webb Space Telescope into music using sonification techniques as part of a multimedia installation project.

How did you get interested in astronomy?  I was always curious about space growing up. I think it comes naturally to children to look up and wonder. In high school, I had a really amazing physics teacher who made me love it and, just as importantly, made me believe I could do it. Around the same time, I started volunteering at the Carnegie Science Center's Buhl Planetarium in Pittsburgh, where I got to teach people of all different ages and knowledge levels about astronomy. Teaching it in that kind of environment made me love it more. I think there's something inspiring about the natural fascination and awe that astronomy strikes in everyone.

I see astronomy, the scientific pursuit, as just one way to understand the universe and our place in it — to connect to the people who came before us and those who will come after, and to make sense of the simultaneous vastness and minuteness of our existence. Those big questions have always really consumed me. When I was around 16 to 18 years old and being asked to figure out what I wanted to do with my life, astronomy felt like a way to swim rather than drown in those questions.

I love that astronomy tugs you in every direction; we think about timescales on the order of billions of years right beside events you'll miss if you blink. I'm also fascinated that we look into the past and try to decipher it, or even use it to predict the future. In that sense, I think astronomers are historians and archaeologists, which resonates with my other interests.

What is your favorite part about Copenhagen? DAWN?  It is genuinely hard to pick a favorite thing about Copenhagen. I love the transportation infrastructure. I’m a huge public transit advocate, and I use it every day here. I also love the many green spaces integrated into the city.

But I think my favorite thing is the arts scene, and the genuine appreciation and respect for art that seems to be woven into the culture of the city. I've been to countless museums, galleries, exhibitions, and performances and still have a never-ending list of more to go to. But it's more than just the major institutions — the city itself is filled with art and design, whether in the fashion, the street art, or the architecture. It feels like life here is understood to be entangled with art, and there's a real investment in that entanglement.

At DAWN, my favorite thing is the sense of community and collaboration. The rigid hierarchy that you find in a lot of academic spaces doesn't seem to really exist here. People want to discuss, share, and spend time together, and they genuinely value each other. I think that's a really ideal environment for anyone, but especially for an undergraduate student.

What motivated you to apply to an international summer research program?  Growing up, my family moved a lot. I graduated high school in Pittsburgh but lived in four other states before Pennsylvania. Moving that frequently was hard in the moment, but in hindsight it shaped me in a lot of good ways. I developed a strong sense of self, because every time you start over you have to look inward and figure out what you actually want, what kinds of friends, what kinds of activities. The fear of going somewhere new disappeared, which made me adventurous.

I think that's a big reason I felt comfortable transferring universities, and a big reason I was drawn to an international program. I had never lived outside the United States for a significant amount of time, so that was naturally an exciting prospect. I love to explore and meet new kinds of people, and I think experiences like this expand my understanding of both the world and myself.

Can you tell me about your summer research project?  I'm working with Joris Witstok and Alex Cameron on exploring a new data release from JADES, a deep survey conducted by JWST that has collected imaging and spectroscopy of galaxies in the early universe — from when the universe was roughly half a billion to about 2 billion years old.

Specifically, I'm investigating how we can use emission line diagnostics to better understand the conditions inside those early galaxies. When galaxies form stars, the radiation from those stars excites the surrounding gas, causing it to emit light at specific wavelengths, which we can see in a spectrum. The ratios between different emission lines can tell us about galaxy properties like their stellar mass, at what rate they are forming stars, and the chemical composition of their gas.

These kinds of diagnostics have been well studied in nearby galaxies, but we've previously been limited to relatively small samples of distant galaxies from the early universe. Now, with this new JADES data release, we have high-quality spectra for over a thousand early galaxies at once, which opens the door to mapping out broader trends and comparing what we observe to predictions from theoretical models. I'm working with both well-known strong emission lines and some less-studied diagnostics. The goal is to build a better empirical picture of how these line ratios relate to other galaxy properties at cosmic dawn.

What skills or knowledge have you been working on developing so far this summer?  I've done research in previous summers, but I'd never worked with high-redshift galaxies before, so a lot of the early work was building up knowledge about the early universe and the new considerations that come with it.

More broadly, I'm working on developing scientific independence — learning to take the research in directions I'm interested in, rather than just completing a set of steps laid out by my advisors. I'm lucky that my mentors have been really encouraging of that, allowing me to explore beyond their suggestions. I won't pretend I'm there yet; it takes a lot of trust in yourself, and that's genuinely hard. But I think it's something I'll gradually get more comfortable with, and it feels like an important part of growing as a scientist.

What Danish word or phrase have you picked up that you now use constantly?  Before the summer started, I went on an Internet hunt for things happening in Denmark during the summer, and I found out about Roskilde Festival — a huge, completely nonprofit, volunteer-run music festival about 30 minutes by train from Copenhagen. If you volunteer at the festival, you get in for free, so I emailed every volunteer group I could find and finally landed a spot selling festival train tickets at Roskilde Station.

The festival was a couple weeks ago, and during my volunteer shifts I picked up the numbers in Danish very quickly as people told me how many tickets they wanted: en billet, to billetter, tre billetter — one ticket, two tickets, three tickets. I also made some great Danish friends at the festival who taught me skål (cheers), though they told me I pronounce it in a very Swedish way. It was an exhausting week as I was going after work and camping there on weekends, but it was completely worth it.