The role of AGN on the structure, kinematics and evolution of ETGs in
  the Horizon simulations
  Feedback processes play a fundamental role in the regulation of the star
formation (SF) activity in galaxies and, in particular, in the quenching of
early-type galaxies (ETGs) as has been inferred by observational and numerical
studies of Lambda CDM models. At z = 0, ETGs exhibit well-known fundamental
scaling relations, but the connection between them and the physical processes
shaping ETG evolution remains unknown.This work aims at studying the impact of
the energetic feedback due to active galactic nuclei (AGN) on the formation and
evolution of ETGs.We focus on assessing the impact of AGN feedback on the
evolution of the mass-plane and the fundamental plane (FP, defined by using
mass surface density) as well as on morphology, kinematics, and stellar age
across the FP.The Horizon-AGN and Horizon-noAGN cosmological hydrodynamical
simulations were performed with identical initial conditions and including the
same physical processes except for the activation of the AGN feedback in the
former. We select a sample of central ETGs from both simulations using the same
criteria and exhaustively study their SF activity, kinematics, and scaling
relations for z <= 3. We find that Horizon-AGN ETGs identified at z = 0 follow
the observed fundamental scaling relations (mass-plane, FP, mass-size relation)
and qualitatively reproduce kinematic features albeit conserving a rotational
inner component with a mass fraction regulated by the AGN feedback. AGN
feedback seems to be required to reproduce the bimodality in the spin parameter
distribution reported by observational works and the mass-size relation (with
more massive galaxies having older stellar populations (SPs), larger sizes, and
being slower rotators). We study the evolution of the fundamental relations
with redshift, finding .Abridged
