Brightest group galaxies and the large-scale environment
  We study the dependence of the properties of group galaxies on the
surrounding large-scale environment, using SDSS-DR7 data. Galaxies are ranked
according to their luminosity within each group and classified morphologically
by the S\'ersic index. We have considered samples of the host groups in
superstructures of galaxies, and elsewhere. We find a significant dependence of
the properties of late-type brightest group galaxies on the large-scale
environment: they show statistically significant higher luminosities and
stellar masses, redder u-r colours, lower star formation activity and longer
star-formation time-scale when embedded in superstructures. By contrast, the
properties of the early-type brightest group galaxies are remarkably similar
regardless of the group global environment. The other group member galaxies
exhibit only the local influence of the group they inhabit. Our analysis
comprises tests against the dependence on the host group luminosity and we
argue that group brightest member properties are not only determined by the
host halo, but also by the large-scale structure which can influence the
accretion process onto their late-type brightest galaxies.
