Constraining Ultra-Light Dark Matter mass with Dwarf Galaxy Rotation Curves

Abstract

While ultra-light bosonic dark matter (ULDM) in a Bose-Einstein condensate (BEC) state could naturally account for the central core in some galaxies and resolve the core-cusp problem, the dark matter density distribution in the outer regions of galaxies remains less explored. We propose a trial wavefunction to model the ULDM distribution beyond the BEC core. We derive the corresponding rotation velocity curve, which shows excellent agreement with those of 12 dwarf spheroidal galaxies. The best-fit ULDM particle mass for each dwarf galaxy falls within a strikingly narrow range of $m=(1.8-3.2)\times 10^{-23}\text{eV}$.