Mg2 gradients as a signature of brightest cluster galaxy evolution
  We have fitted the Mg2 absorption index gradients for 21 brightest cluster
galaxies (BCGs), in the nearby Universe, for which we have obtained high
signal-to-noise ratio, long-slit spectra on the Gemini telescopes. This is a
sub-sample of a large optical, spatially-resolved, spectroscopic sample of BCGs
which allows possible connections between the kinematical, dynamical and
stellar population properties to be studied. We find a weak correlation between
the Mg2 gradients and central velocity dispersion, with gradients becoming
steeper with increasing mass. An equivalent correlation for normal ellipticals
in the same mass range is not found, suggesting that the BCG stellar population
profiles are shaped by mechanisms related to the potential well of the cluster
where they live. This suggestion is reinforced by the existence of a
correlation between the Mg2 gradients and the BCG distance to the X-ray peak
luminosity of the cluster.
