Undergraduate student may have solved puzzle regarding isolated galaxies that have stopped producing stars

Key Points:

• Julian Shapiro, an undergraduate astrophysics student at UC Berkeley, discovered three unusual isolated dwarf galaxies—Shapiro Dwarf Galaxies I, II, and III—that have stopped forming stars, a rare combination challenging existing understanding.
• The galaxies may be "backsplash" galaxies, having passed close to a massive host galaxy like Messier 101, which stripped their star-forming gas before ejecting them into isolation, supporting predictions of the standard lambda-cold dark matter (ΛCDM) cosmological model.
• Shapiro used simulations and telescope archive data to identify these candidates and proposed new methods for predicting backsplash galaxy frequency, with hopes that future telescopes like the Vera C. Rubin Observatory will uncover more such galaxies.
• Remarkably, Shapiro conducted much of this research while still in high school, earning recognition as a 2026 Davidson Fellow and the 2025 Astronomical League's National Young Astronomer Award, highlighting the potential for young researchers to make significant contributions using public data.
• Berkeley astronomy professor Alex Filippenko praised Shapiro's sophisticated work and welcomed him to UC Berkeley's astrophysics program, where Shapiro continues his studies and research.