The formation of the brightest cluster galaxies in cosmological
  simulations: the case for AGN feedback
  We use 500 pc resolution cosmological simulations of a Virgo-like galaxy
cluster to study the properties of the brightest cluster galaxy (BCG) that
forms at the center of the halo. We compared two simulations; one incorporating
only supernovae feedback and a second that also includes prescriptions for
black hole growth and the resulting AGN feedback from gas accretion. As
previous work has shown, with supernovae feedback alone we are unable to
reproduce any of the observed properties of massive cluster ellipticals. The
resulting BCG is rotating quickly, has a high Sersic index, a strong mass
excess in the center and a total central density profile falling more steeply
than isothermal. Furthermore, it is far too efficient at converting most of the
available baryons into stars which is strongly constrained by abundance
matching. With a treatment of black hole dynamics and AGN feedback the BCG
properties are in good agreement with data: they rotate slowly, have a cored
surface density profile, a flat or rising velocity dispersion profile and a low
stellar mass fraction. The AGN provides a new mechanism to create cores in
luminous elliptical galaxies; the core expands due to the combined effects of
heating from dynamical friction of sinking massive black holes and AGN feedback
that ejects gaseous material from the central regions.
