Stellar populations across the black hole mass - velocity dispersion
  relation
  Coevolution between supermassive black holes (BHs) and their host galaxies is
universally adopted in models for galaxy formation. In the absence of feedback
from active galactic nuclei, simulated massive galaxies keep forming stars in
the local Universe. From an observational point of view, however, such
coevolution remains unclear. We present a stellar population analysis of
galaxies with direct BH mass measurements and the BH mass-{\sigma} relation as
a working framework. We find that over-massive BH galaxies, i.e., galaxies
lying above the best-fitting BH mass-{\sigma} line, tend to be older and more
{\alpha}-element enhanced than under-massive BH galaxies. The scatter in the BH
mass-{\sigma}-[{\alpha}/Fe] plane is significantly lower than in the standard
BH mass-{\sigma} relation. We interpret this trend as an imprint of active
galactic nucleus feedback on the star formation histories of massive galaxies.
