A fraction of light scalar dark matter, especially axions, may organize into Bose-Einstein condensates, gravitationally bound clumps, "boson stars", and be present in large number galactic halos today. We compute the expected gravitational microlensing events clumps composed ordinary QCD axion axion-like-particles derive constraints from EROS-2 survey Subaru Hyper Suprime-Cam observation. perfo...
