The accretion histories of brightest cluster galaxies from their stellar
  population gradients
  We analyse the spatially-resolved stellar populations of 9 local ($z<0.1$)
Brightest Cluster Galaxies (BCGs) observed with VIMOS in IFU mode. Our sample
is composed of 7 slow-rotating and 2 fast-rotating BCGs. We do not find a
connection between stellar kinematics and stellar populations in this small
sample. The BCGs have shallow metallicity gradients (median $\Delta$[Fe/H] $=
-0.11\pm0.1$), high central metallicities (median $[$Fe/H]$_{[\alpha/Fe]=0} =
0.13\pm0.07$), and a wide range of central ages (from 5 to 15 Gyr). We propose
that the reason for this is diverse evolutionary paths in BCGs. 67 per cent of
the sample (6/9) show $\sim 7$ Gyr old central ages, which reflects an active
accretion history, and 33 per cent of the sample (3/9) have central ages older
than 11 Gyr, which suggest no star formation since $z=2$. The BCGs show similar
central stellar populations and stellar population gradients to early-type
galaxies of similar mass (M$_{dyn}> 10^{11.3}$M$_{\odot}$) from the
ATLAS$^{3D}$ survey (median [Z/H] $= 0.04\pm0.07$, $\Delta$[Z/H] $=
-0.19\pm0.1$). However, massive early-type galaxies from ATLAS$^{3D}$ have
consistently old ages (median Age $=12.0\pm3.8$Gyr). We also analyse the close
massive companion galaxies of two of the BCGs. These galaxies have similar
stellar populations to their respective BCGs.
