An Ordered Bipolar Outflow from a Massive Early-Stage Core
  We present ALMA follow-up observations of two massive, early-stage core
candidates, C1-N & C1-S, in Infrared Dark Cloud (IRDC) G028.37+00.07, which
were previously identified by their N2D+(3-2) emission and show high levels of
deuteration of this species. The cores are also dark at far infrared
wavelengths up to ~100 microns. We detect 12CO(2-1) from a narrow,
highly-collimated bipolar outflow that is being launched from near the center
of the C1-S core, which is also the location of the peak 1.3mm dust continuum
emission. This protostar, C1-Sa, has associated dense gas traced by C18O(2-1)
and DCN(3-2), from which we estimate it has a radial velocity that is near the
center of the range exhibited by the C1-S massive core. A second
outflow-driving source is also detected within the projected boundary of C1-S,
but appears to be at a different radial velocity. After considering properties
of the outflows, we conclude C1-Sa is a promising candidate for an early-stage
massive protostar and as such it shows that these early phases of massive star
formation can involve highly ordered outflow, and thus accretion, processes,
similar to models developed to explain low-mass protostars.
