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 } \mathrm { eV } , consistent with other constraints from galaxy dynamics but in tension with constraints from Ly \alpha forest power spectrum modeling .
While we are unable to statistically distinguish between fuzzy DM and “ normal ” cold DM models , we find that the inferred properties of the fuzzy DM halo satisfy a number of predictions for halos in a fuzzy DM cosmology .
In particular , we find good agreement with the predicted core size–halo mass relation and the predicted transition radius between the quantum pressure-dominated inner region and the outer halo region .