Do dark matter collisions explain why some dwarf galaxies are missing their centers?

Self-interacting dark matter can behave like a gas, heating up or cooling down depending on conditions. Simulations of ten-billion-solar-mass halos show that violent mergers pump energy into the core, either blocking its collapse or driving it to unusually low densities—effects standard models miss. This suggests merger history, not just halo size, shapes the central structure of dwarf galaxies.