The black hole - bulge mass relation of Active Galactic Nuclei in the
  Extended Chandra Deep Field - South Survey
  We present results from a study to determine whether relations, established
in the local Universe, between the mass of supermassive black holes (SMBHs) and
their host galaxies are in place at higher redshifts. We establish a
well-constructed sample of 18 X-ray-selected, broad-line Active Galactic Nuclei
(AGN) in the Extended Chandra Deep Field South - Survey with 0.5 < z < 1.2.
This redshift range is chosen to ensure that HST imaging is available with at
least two filters that bracket the 4000 Angstrom break thus providing reliable
stellar mass estimates of the host galaxy by accounting for both young and old
stellar populations. We compute single-epoch, virial black hole masses from
optical spectra using the broad MgII emission line. For essentially all
galaxies in our sample, their total stellar mass content agrees remarkably
well, given their BH masses, with local relations of inactive galaxies and
active SMBHs. We further decompose the total stellar mass into bulge and disk
components separately with full knowledge of the HST point-spread-function. We
find that ~80% of the sample is consistent with the local M_BH - M_Bulge
relation even with 72% of the host galaxies showing the presence of a disk. In
particular, bulge dominated hosts are more aligned with the local relation than
those with prominent disks. We further discuss the possible physical mechanisms
that are capable building up the stellar mass of the bulge from an extended
disk of stars over the subsequent eight Gyrs.
