ALMA observations and modeling of the rotating outflow in Orion Source I
  We present $^{29}$SiO(J=8--7) $\nu$=0, SiS (J=19--18) $\nu$=0, and $^{28}$SiO
(J=8--7) $\nu$=1 molecular line archive observations made with the Atacama
Large Millimeter/Submillimeter Array (ALMA) of the molecular outflow associated
with Orion Source I. The observations show velocity asymmetries about the flow
axis which are interpreted as outflow rotation. We find that the rotation
velocity ($\sim$4--8 km s$^{-1}$) decreases with the vertical distance to the
disk. In contrast, the cylindrical radius ($\sim$100--300 au), the expansion
velocity ($\sim$2--15 km s$^{-1}$), and the axial velocity $v_{\rm z}$
($\sim$-1--10 km s$^{-1}$) increase with the vertical distance. The mass
estimated of the molecular outflow $\mathrm{M}_{\rm outflow}\sim$0.66--1.3
M$_\odot$. Given a kinematic time $\sim$130 yr, this implies a mass loss rate
$\dot{\mathrm{M}}_{\rm outflow} \sim 5.1-10 \times 10^{-3}$ M$_\odot$
yr$^{-1}$. This massive outflow sets important contraints on disk wind models.
We compare the observations with a model of a shell produced by the interaction
between an anisotropic stellar wind and an Ulrich accretion flow that
corresponds to a rotating molecular envelope in collapse. We find that the
model cylindrical radii are consistent with the $^{29}$SiO(J=8--7) $\nu$=0
data. The expansion velocities and the axial velocities of the model are
similar the observed values, except close to the disk ($z\sim\pm$150 au) for
the expansion velocity. Nevertheless, the rotation velocities of the model are
a factor $\sim$3--10 lower than the observed values. We conclude that the
Ulrich flow alone cannot explain the rotation observed and other possibilities
should be explored, like the inclusion of the angular momentum of a disk wind.
