Spatially Resolved Stellar Kinematics of the Ultra-Diffuse Galaxy Dragonfly 44: II. Constraints on Fuzzy Dark Matter

Understand

Given the absence of directly detected dark matter (DM) as weakly interacting massive particles, there is strong interest in the possibility that DM is an ultra-light scalar field, here denoted as fuzzy DM.

• Ultra-diffuse galaxies, with the sizes of giant galaxies and the luminosities of dwarf galaxies, have a wide range of DM halo masses, thus providing new opportunities for exploring the connections between galaxies and their DM halos.
• Following up on new integral field unit spectroscopic observations and dynamics modeling of the DM-dominated ultra-diffuse galaxy Dragonfly 44 in the outskirts of the Coma Cluster, we present models of fuzzy DM constrained by the stellar dynamics of this galaxy.
• We infer a scalar field mass of $\sim 3 \times 10^{-22}$ eV, consistent with other constraints from galaxy dynamics but in tension with constraints from Ly$\alpha$ forest power spectrum modeling.