  We report adaptive optics H- and K-band spectroscopy of the inner few arcsec
of the luminous merger/ULIRG/QSO Mkn231, at spatial resolutions as small as
0.085". For the first time we have been able to resolve the active star forming
region close to the AGN using stellar absorption features, finding that its
luminosity profile is well represented by an exponential function with a disk
scale length 0.18-0.24" (150-200pc), and implying that the stars exist in a
disk rather than a spheroid. The stars in this region are also young
(10-100Myr), and it therefore seems likely that they have formed in situ in the
gas disk, which itself resulted from the merger. The value of the stellar
velocity dispersion is a result of the large mass surface density of the disk.
The stars in this region have a combined mass of at least 1.6x10^9M_sun, and
account for 25-40% of the bolometric luminosity of the entire galaxy. We have
detected the 2.12um 1-0S(1) H_2 and 1.64um [FeII] lines out to radii exceeding
0.5". The kinematics for the two lines are very similar to each other as well
as to the stellar kinematics, and broadly consistent with the nearly face-on
rotating disk reported in the literature and based on interferometric CO1-0 and
CO2-1 measurements of the cold gas. However, they suggest a more complex
situation in which the inner 0.2-0.3" (200pc) is warped out of its original
disk plane. Such a scenario is supported by other observations.
