Total density profile of massive early-type galaxies in Horizon-AGN
  simulation: impact of AGN feedback and comparison with observations
  Using the two large cosmological hydrodynamical simulations, Horizon-AGN
(H-AGN) and Horizon-noAGN (H-noAGN, no AGN feedback), we investigate how a
typical sub-grid model for AGN feedback affects the evolution of the total
density profiles (dark matter + stars) at the effective radius of massive
early-type galaxies (M*>10^11 Msun). We have studied the dependencies of the
mass-weighted density slope gamma'_tot with the effective radius, the galaxy
mass and the host halo mass at z~0.3 and found that the inclusion of AGN
feedbackalways leads to a much better agreement with observational values and
trends. Our analysis suggests also that the inclusion of AGN feedback favours a
strong correlation between gamma'_tot and the density slope of the dark matter
component while, in the absence of AGN activity, gamma'_tot is rather strongly
correlated with the density slope of the stellar component. Finally, we find
that gamma'_tot derived from our samples of galaxies increases from z=2 to
z=0,in good agreement with the expected observational trend. The derived slopes
are slightly lower than in the data when AGN is included because the simulated
galaxies tend to be too extended, especially the least massive ones. However,
the simulated compact galaxies without AGN feedback have gamma'_tot values that
are significantly too high compared to observations.
