The mass relations between supermassive black holes and their host
  galaxies at 1<z<2 with HST-WFC3
  Correlations between the mass of a supermassive black hole and the properties
of its host galaxy (e.g., total stellar mass (M*), luminosity (Lhost)) suggest
an evolutionary connection. A powerful test of a co-evolution scenario is to
measure the relations MBH-Lhost and MBH-M* at high redshift and compare with
local estimates. For this purpose, we acquired HST imaging with WFC3 of 32
X-ray-selected broad-line AGN at 1.2<z<1.7 in deep survey fields. By applying
state-of-the-art tools to decompose the HST images including available ACS
data, we measured the host galaxy luminosity and stellar mass along with other
properties through the 2D model fitting. The black hole mass was determined
using the broad Halpha line, detected in the near-infrared with Subaru/FMOS,
which potentially minimizes systematic effects using other indicators. We find
that the observed ratio of MBH to total M* is 2.7 times larger at z~1.5 than in
the local universe, while the scatter is equivalent between the two epochs. A
non-evolving mass ratio is consistent with the data at the 2-3 sigma confidence
level when accounting for selection effects and their uncertainties. The
relationship between MBH-Lhost paints a similar picture. Therefore, our results
cannot distinguish whether SMBHs and their total M* and Lhost proceed in
lockstep or whether the growth of the former somewhat overshoots the latter,
given the uncertainties. Based on a statistical estimate of the bulge-to-total
mass fraction, the ratio MBH/M* is offset from the local value by a factor of
~7 which is significant even accounting for selection effects. Taken together,
these observations are consistent with a scenario in which stellar mass is
subsequently transferred from an angular momentum supported component of the
galaxy to the pressure supported one through secular processes or minor mergers
at a faster rate than mass accretion onto the SMBH.
