We present ALMA CO(2-1) observations toward a massive infrared dark cloud
G28.37+0.07. The ALMA data reveal numerous molecular (CO) outflows with a wide
range of sizes throughout the cloud. Sixty-two 1.3 mm continuum cores were
identified to be driving molecular outflows. We have determined the position
angle in the plane-of-sky of 120 CO outflow lobes and studied their
distribution. We find that the distribution of the plane-of-sky outflow
position angles peaks at about 100 degree, corresponding to a concentration of
outflows with an approximately east-west direction. For most outflows, we have
been able to estimate the plane-of-sky angle between the outflow axis and the
filament that harbors the protostar that powers the outflow. Statistical tests
strongly indicate that the distribution of outflow-filament orientations is
consistent with most outflow axes being mostly orthogonal to their parent
filament in 3D. Such alignment may result from filament fragmentation or
continuous mass transportation from filament to the embedded protostellar core.
The latter is suggested by recent numerical studies with moderately strong
magnetic fields.Comment: 4 figures, 1 table, accepted by Ap
