Kareem El-Badry, Keck Observatory observer and assistant professor at the California Institute of Technology, has been named a 2025 MacArthur Fellow for his groundbreaking work on “expanding our knowledge of binary star systems, black holes, and other wonders of the universe.”
Awarded by the The John D. and Catherine T. MacArthur Foundation, the prestigious fellowship recognizes individuals across disciplines whose creativity and insight push the boundaries of what’s possible. Kareem joins a distinguished group of “creative geniuses” celebrated for their ability to make lasting societal impact.
This honor caps a breakthrough year for Kareem, who was also selected as a 2025 Sloan Research Fellow, awarded annually to early-career researchers whose creativity, innovation, and research accomplishments make them stand out as the next generation of leaders.
We recently caught up with Kareem to talk about his research, his long-standing connection to Keck, and how creativity in science thrives through collaboration.
1. How does it feel to earn two major awards in the same year? How will these awards impact your research?
[Kareem]: Well, I’d say it feels pretty good! I appreciate that both awards come with minimal restrictions, giving me the opportunity to explore new or potentially risky projects that would be harder to get funded through a federal grant.
While it of course feels nice to be recognized individually, I should note that my work is done with other people: much of it is done in large collaborations (like Gaia and The Sloan Digital Sky Survey), and even the smaller projects are mostly done with students and postdocs. I view these awards partially as recognition for these collaborative projects, not just my own accomplishments.
2. What aspect of the work that led to the MacArthur Award excites you the most?
[Kareem]: I like the whole process of searching through large datasets, finding interesting objects, getting more data to understand them better, and using the observations to test physical models. Astronomical data are often complicated. Studying binaries, we can find dozens of different classes of objects that behave in different ways, evolve on different timescales, emit light at different frequencies, etc.. but after we make sense of all the data, we can sometimes understand it through a few relatively simple physics concepts. We find that objects that look very different from each other are sometimes closely related, but just at different evolutionary stages, or started with slightly different initial conditions. I get excited when I can find connections like that, coming up with the best story to explain different pieces of data that seemed unrelated at first.
3. How important is Keck Observatory to your MacArthur Award now or to your work in the future?
[Kareem]: Extremely important! My normal workflow is to search data from large-scale surveys for interesting objects, and then use Keck to study a few of them in more detail. In the last few years, I’ve used HIRES, LRIS, KPF, ESI, DEIMOS, NIRC2, KCWI, and NIRES, all for studying different kinds of binaries. Probably the most important instrument for me is HIRES, which I use to get high-resolution, multi-epoch spectroscopy in the near UV / far blue optical. When we’re looking for black hole companions to stars, one of the most common false-positives that we need to rule out are mass-transfer binaries that have a faint, blue star orbited by a brighter, redder star. HIRES is especially useful for detecting these faint, blue companions, and I hope to keep using it to find black holes after the next Gaia data release, which is coming next year! I’m also involved in building a new instrument, called Zshooter, which will eventually replace HIRES and have higher sensitivity.
4. What advice do you have for us aspiring “geniuses”?
[Kareem]: I think I’ve benefited a lot from the freedom to explore different areas within astrophysics and expose myself to different ideas. It’s much easier to have a creative idea that connects themes from different subfields when you read about and talk to people working in different areas. At all stages in a research career, I think it’s important to look for opportunities to branch out and try something new. Of course, so much of what we do in astronomy relies on collaboration and on technological innovations that are the result of many people’s work. A genius might just be someone who positioned themselves to take advantage of new data and capabilities when they became available! I think it’s nice to celebrate individual accomplishments, particularly when they expose people who wouldn’t otherwise learn about science or astronomy to new research, but we should remember that much of the work is collaborative.
Hoʻomaikaʻi, Kareem, and mahalo nui for sharing your naʻauao – your wisdom and insight – with us.
Related Links:
Kareem El-Badry Named a 2025 MacArthur Fellow – Caltech News
Trio of Caltech Professors Named Sloan Fellows – Caltech News