On the dark matter content of ultra-diffuse galaxies

I compare the dark matter content within stellar half-mass radius expected in a $\Lambda$CDM-based galaxy formation model with existing observational estimates for the observed dwarf satellites of the Milky Way and ultra-diffuse galaxies (UDGs).

The model reproduces the main properties and scaling relations of dwarf galaxies, in particular their stellar mass-size relation.

I show that the model also reproduces the relation between the dark matter mass within the half-mass radius, $M_{\rm dm}(

The scatter in the $M_{\rm dm}(

I also show the $M_{\rm dm}(

The upper limits on $M_{\rm dm}(

The most dark matter-deficient galaxies of a given size correspond to halos with the smallest concentrations and the largest ratios of $M_\star/M_{\rm 200c}$.

Conversely, the most dark matter-dominated galaxies are hosted by the highest concentration halos with the smallest $M_\star/M_{\rm 200c}$ ratios.

Results presented in this paper indicate that dark matter content of observed UDGs may represent a tail of the expected dark matter profiles, especially if the effect of feedback on these profiles is taken into account.

Nevertheless, the unusually rich GC populations in some UDG galaxies do indicate unusual evolution.

Our results simply indicate that with the current accuracy of the velocity dispersion measurements their $M_{\rm dm}(

;Comment: 10 pages, 7 figures, final version accepted in the Open Journal of Astrophysics