Massive relic galaxies challenge the co-evolution of SMBHs and their
  host galaxies
  We study a sample of eight massive galaxies that are extreme outliers
(3-5$\sigma$) in the M$_{\bullet}$-M$_\mathrm{bulge}$ local scaling relation.
Two of these galaxies are confirmed to host extremely large super massive black
holes (SMBHs), whereas the virial mass estimates for the other six are also
consistent with having abnormally large SMBHs. From the analysis of their star
formation histories and their structural properties we find that all these
extreme outliers can be considered as relic galaxies from the early (z$\sim$2)
Universe: i.e. they are compact (R$_{\mathrm{e}}$$<$2 kpc) and have purely old
stellar populations (t$\gtrsim$10 Gyr). In order to explain the nature of such
deviations from the local relations, we propose a scenario in which the hosts
of these \"uber-massive SMBHs are galaxies that have followed a different
evolutionary path than the two-phase growth channel assumed for massive
galaxies. Once the SMBH and the core of the galaxy are formed at z$\sim$2, the
galaxy skips the second phase, remaining structurally untouched and without
further mass and size increase. We show that if the outliers had followed the
normal evolutionary path by growing in size via merger activity, the expected
(mild) growth in mass would place them closer to the observed local relations.
Our results suggest that the SMBH growth epoch for the most massive galaxies
stopped $\sim$10Gyr ago.
