The low-mass end of the Mbh/Mhost relation in quasars
  The Mbh-Mhost relation in quasars has been probed only in a limited parameter
space, namely at Mbh~10^9 Msun and Mhost~10^12 Msun. Here we present a study of
26 quasars lying in the low-mass end of the relation, down to Mbh~10^7 Msun. We
selected quasars from the SDSS and HST-FOS archives, requiring modest Mbh (as
derived through the virial paradigm). We imaged our sources in H band from the
Nordic Optical Telescope. The quasar host galaxies have been resolved in 25 out
of 26 observed targets. Host galaxy luminosities and stellar masses are
computed, under reasonable assumptions on their star formation histories.
Combining these results with those from our previous studies, we manage to
extend the sampled parameter space of the Mbh-Mhost relation in quasars. The
relation holds over 2 dex in both the parameters, similarly to what observed in
low-luminosity AGN and in quiescent galaxies. For the first time, we are able
to measure the slope of the Mbh-Mhost relation in quasars. We find that it is
consistent with the linear case (similarly to what observed in quiescent
galaxies). We do not find any evidence of a population of massive black holes
lying below the relation.
