Kareem El-Badry Wins Packard Fellowship

Kareem El-Badry, associate professor of astronomy at Caltech, has been selected as one of 20 Packard Fellows for 2026. The Packard Fellowships for Science and Engineering provide just under $990,000 in unrestricted funds for early career researchers to use over a five-year period.

Much of El-Badry's work involves uncovering hidden populations of black holes. Our Milky Way galaxy is teeming with millions of these extremely dense objects, usually created when massive dead stars explode and then collapse inward under their own gravity. But black holes are hard to find. El-Badry reveals the cosmic objects using data from large-scale surveys, such as the European Space Agency's Gaia mission, along with targeted spectroscopy. One method involves looking for telltale stellar motions, or wobbles, caused by the gravitational tugs of orbiting black holes.

"Massive stars live short but exciting lives," El-Badry says. "They are the primary sources of energy, momentum, and ionizing radiation in the galaxy. Their deaths give rise to spectacular cosmic explosions, and they produce most of the elements from which planets form. Today, the Milky Way contains a few tens of thousands of massive stars. But for every massive star alive today, there are about 1,000 that have already died. These dead massive stars amount to a stellar graveyard of black holes and neutron stars." (Neutron stars are dense remnants that form out of the explosions of massive stars whose cores were not quite dense enough to form black holes.)

In recent work, El-Badry discovered the closest-known black hole to Earth, located about 1,600 light-years away; 21 hidden neutron stars orbiting around stars like our Sun; and the first-known "black hole triple," a system of three stars, one of which is a black hole.

"By measuring the masses, velocities, and companions of these hidden black holes and neutron stars, we can learn about the lives and deaths of the massive stars from which they formed," El-Badry says.

El-Badry learned that he had won a Packard Fellowship after Hirosi Ooguri, the Kent and Joyce Kresa Leadership Chair of Caltech's Division of Physics, Mathematics and Astronomy, invited him to a Zoom call to discuss his research. Unbeknownst to El-Badry, Ooguri had planned for a representative of the Packard Foundation to join the call and deliver the good news.

"I thought this was a routine meeting with Hirosi, so when someone else joined the call, I wondered if I'd done something wrong," El-Badry jokes.

"Kareem has a remarkable ability to turn vast astronomical datasets into discoveries about how stars evolve," Ooguri says. "The Packard Fellowship will give him the freedom to pursue bold ideas. I look forward to the discoveries that he will make, addressing questions about our universe and posing new ones."

El-Badry is looking ahead to analyzing new data from Gaia and from NASA missions including SPHEREx, the Nancy Grace Roman Space Telescope, and UVEX, on whose team he serves.

He earned his undergraduate degree from Yale University and his PhD in astrophysics from UC Berkeley, and he was a postdoctoral researcher at the Harvard & Smithsonian Center for Astrophysics before joining Caltech. He was named a Sloan Research Fellow and a MacArthur Fellow in 2025.

This year, the Packard Foundation expanded its support for fellows from $875,000 to $985,834 over five years. According to the foundation, "Fellows decide what their research needs, whether that is new equipment, another researcher on the team, travel to a conference, or child care during the demanding early years of running a lab. That flexibility lets Fellows test novel ideas, follow unexpected findings, and lead research that drives real-world impact."

Other Caltech-affiliated winners of 2026 Packard fellowships include alumni Kurtis Carsch (BS/MS '16), an assistant professor of chemistry at the University of Texas at Austin, and three former Caltech postdocs: Soumitra Athavale, an assistant professor of chemistry and biochemistry at UCLA; Liam Connor, an assistant professor of astronomy at Harvard University; and Nathanan Tantivasadakarn, an assistant professor of physics and astronomy at Stony Brook University.

For more information about the Packard Foundation, visit their website.