Andrés along the famous tree-lined path at Assistens Cemetery in Copenhagen, the resting place of Hans Christian Andersen, Niels Bohr, and other Danish luminaries.
Tell me a little about yourself: I was born in Venezuela and moved to the United States when I was 10 years old, settling in Weston, Florida, near Fort Lauderdale. I did my middle and high school years there before heading to Yale University, where I study physics and computer science. All of my research, though, is in the astronomy department, where I work with Prof. Earl Bellinger in the Yale Astro ML group. We apply machine learning to asteroseismology, the study of stellar interiors through the oscillations stars make, a bit like using seismic waves to probe Earth's interior.
I originally applied to Yale as an astrophysics student, then switched to a physics major between freshman and sophomore year when I wasn't sure what I wanted to commit to. Though, at this point, I've come around and will probably end up in astronomy anyway. One thing I didn't expect from Yale was how much the liberal arts side of it would shape how I think. I originally wanted to go somewhere more technical, like MIT or Georgia Tech, and thought I had no business taking non-STEM classes. Having them essentially required has turned out to be one of the best things about my time there.
How did you get interested in astronomy? I wanted to be an astronaut when I was little (pretty standard) and that interest just kind of carried through as I grew up. I watched a lot of pop science content about astronomy, especially the YouTube channel Kurzgesagt, which made really entertaining videos about big ideas in physics and space. I also knew early on that I liked physics and computer science from my classes, so astronomy felt like the natural intersection of all of it.
What is your favorite part about Copenhagen? DAWN? The bike infrastructure here is genuinely remarkable. I’ve been riding around a lot, and the whole city just makes it easy. I grew up going to Universal Studios, so I'm used to amusement parks being hectic and loud, but even Tivoli felt completely different, more like a beautifully manicured garden than a theme park. Copenhagen just seems to have its priorities in the right place when it comes to parks and public space. It feels like a very healthy city to live in.
At DAWN, I love how many opportunities there are to interact with everyone. The communal lunch, where the whole group grabs food and sits together at a big long table, is something I'd never experienced at quite that scale before. And the Cake Talks, where researchers give informal presentations over cake, have been a great way to get a broad view of the different things people are working on, even when some of it is a bit beyond my level to follow in full detail.
What motivated you to apply to an international summer research program? I haven't done a lot of travel since starting high school, and this felt like a real opportunity to step outside my comfort zone. Everyone tells you to study abroad, but as a physics major it's hard to make work, so this is my version of it. I've also never been away from family for quite this long, though I can't claim to be a total stranger to big transitions, having moved to a whole new country at age 10.
A JWST image of a galaxy group in GOODS-South seen when the Universe was about 2 billion years old. The three interacting galaxies, nicknamed "The Good, the Bad, and the Ugly" by the research team, include a dormant galaxy, a mysterious compact red object, and a dusty star-forming galaxy. Andrés is working to characterize each one and understand whether their interactions have shaped their very different fates.
Can you tell me about your summer research project? The project is focused on a really interesting system in GOODS-South, a region of the sky that has been imaged deeply by both the James Webb Space Telescope and the Hubble Space Telescope. What makes this system exciting is that it appears to contain four very different types of galaxies — a star-forming galaxy, a "little red dot" (mysterious compact objects seen in the early universe that have sparked a lot of debate about what they actually are), a dusty star-forming galaxy, and a quiescent (dormant) galaxy — all at roughly the same distance from us, and apparently interacting with each other.
The project has two connected goals. The first is to characterize each of these galaxies individually, figuring out their masses, how quickly they are forming stars, and their histories by modeling these properties from the light we observe. The second goal is to understand the broader environment: we think these galaxies may be part of an overdensity, an early cluster where many galaxies have gravitationally gathered together in the same region of space. If the dormant galaxy has stopped forming stars partly because of its interactions with its neighbors, that could be evidence of "environmental quenching" — the idea that a galaxy's surroundings can play a direct role in shutting down its star formation.
As a side note: while getting set up with the tools early on, I found and fixed a bug in EAzY, a widely used software for estimating galaxy distances from their light. The developer, Gabe Brammer (who is faculty here at DAWN) , added me as a contributor to the project. I thought that was very generous for a one-line fix, but I appreciated it a lot.
What skills or knowledge have you been working on developing so far this summer? I feel fairly confident in my technical abilities and the coding side of things. What I'm hoping to develop more is the scientific judgment side by getting better at reading papers and building enough understanding of what I'm doing to be able to pick my own next direction rather than immediately checking in with my advisor every time I finish a step. Those are harder skills to develop, but I think this summer is a good place to start. The workshops have helped. Particularly Will's session on how to read a scientific paper, which was genuinely useful because my advisor has already been sending me papers to get through.
What Danish word or phrase have you picked up that you now use constantly? Undskyld mig, or “excuse me.” I learned it out of necessity when I first started biking, because I was a little reckless and needed it fairly often. I'd say I've improved since then. I've also been trying to learn Danish on Duolingo so I could at least read grocery store labels — though I have yet to meet a single person in Copenhagen who doesn't speak perfect English, so the practical urgency has been limited.