We make a direct comparison of the derived dark matter ( DM ) distributions between hydrodynamical simulations of dwarf galaxies assuming a \Lambda CDM cosmology and the observed dwarf galaxies sample from the THINGS survey in terms of ( 1 ) the rotation curve shape and ( 2 ) the logarithmic inner density slope \alpha of mass density profiles .
The simulations , which include the effect of baryonic feedback processes , such as gas cooling , star formation , cosmic UV background heating and most importantly physically motivated gas outflows driven by supernovae ( SNe ) , form bulgeless galaxies with DM cores .
We show that the stellar and baryonic mass is similar to that inferred from photometric and kinematic methods for galaxies of similar circular velocity .
Analyzing the simulations in exactly the same way as the observational sample allows us to address directly the so-called “ cusp/core ” problem in the \Lambda CDM model .
We show that the rotation curves of the simulated dwarf galaxies rise less steeply than CDM rotation curves and are consistent with those of the THINGS dwarf galaxies .
The mean value of the logarithmic inner density slopes \alpha of the simulated galaxies ’ dark matter density profiles is \sim -0.4 \pm 0.1 , which shows good agreement with \alpha = -0.29 \pm 0.07 of the THINGS dwarf galaxies .
The effect of non-circular motions is not significant enough to affect the results .
This confirms that the baryonic feedback processes included in the simulations are efficiently able to make the initial cusps with \alpha \sim -1.0 to -1.5 predicted by dark-matter-only simulations shallower , and induce DM halos with a central mass distribution similar to that observed in nearby dwarf galaxies .