High-resolution imaging of the molecular outflows in two mergers:
  IRAS17208-0014 and NGC1614
  Galaxy evolution scenarios predict that the feedback of star formation and
nuclear activity (AGN) can drive the transformation of gas-rich spiral mergers
into ULIRGs, and, eventually, lead to the build-up of QSO/elliptical hosts. We
study the role that star formation and AGN feedback have in launching and
maintaining the molecular outflows in two starburst-dominated advanced mergers,
NGC1614 and IRAS17208-0014, by analyzing the distribution and kinematics of
their molecular gas reservoirs. We have used the PdBI array to image with high
spatial resolution (0.5"-1.2") the CO(1-0) and CO(2-1) line emissions in
NGC1614 and IRAS17208-0014, respectively. The velocity fields of the gas are
analyzed and modeled to find the evidence of molecular outflows in these
sources and characterize the mass, momentum and energy of these components.
While most (>95%) of the CO emission stems from spatially-resolved
(~2-3kpc-diameter) rotating disks, we also detect in both mergers the emission
from high-velocity line wings that extend up to +-500-700km/s, well beyond the
estimated virial range associated with rotation and turbulence. The kinematic
major axis of the line wing emission is tilted by ~90deg in NGC1614 and by
~180deg in IRAS17208-0014 relative to their respective rotating disk major
axes. These results can be explained by the existence of non-coplanar molecular
outflows in both systems. In stark contrast with NGC1614, where star formation
alone can drive its molecular outflow, the mass, energy and momentum budget
requirements of the molecular outflow in IRAS17208-0014 can be best accounted
for by the existence of a so far undetected (hidden) AGN of L_AGN~7x10^11
L_sun. The geometry of the molecular outflow in IRAS17208-0014 suggests that
the outflow is launched by a non-coplanar disk that may be associated with a
buried AGN in the western nucleus.
