Gamma Rays from the Littlest Galaxies: Tracing Accretion and Dark Matter in the Low-Mass Universe

Now in its 17th year of operation, the Fermi Large Area Telescope (LAT) continues to transform our understanding of the smallest galaxies in the Universe. Dwarf galaxies host some of the most extreme environments known—from ultra-faint systems dominated by dark matter to those harboring actively accreting intermediate-mass black holes (IMBHs). In the first part of this talk, I will present results from the first systematic Fermi-LAT search for gamma-ray emission from active galactic nuclei in dwarf galaxies, revealing hints of a soft-spectrum excess that may trace the onset of high-energy activity in low-mass black holes. In the second part, I will discuss our complementary search for dark matter annihilation in dwarf galaxies, including limits from ultra-faint systems. Together, these studies illustrate how the littlest galaxies provide powerful and complementary laboratories in gamma rays—probing both the physics of black hole growth and the nature of dark matter. Looking ahead, I will address the (exciting) uncertainties and challenges facing space-based gamma-ray astronomy, as well as highlight the promising prospects offered by next-generation ground-based gamma-ray observatories.