Investigating the Complex Velocity Structures within Dense Molecular
  Cloud Cores with GBT-Argus
  We present the first results of high-spectral resolution (0.023 km/s)
N$_2$H$^+$ observations of dense gas dynamics at core scales (~0.01 pc) using
the recently commissioned Argus instrument on the Green Bank Telescope (GBT).
While the fitted linear velocity gradients across the cores measured in our
targets nicely agree with the well-known power-law correlation between the
specific angular momentum and core size, it is unclear if the observed
gradients represent core-scale rotation. In addition, our Argus data reveal
detailed and intriguing gas structures in position-velocity (PV) space for all
5 targets studied in this project, which could suggest that the velocity
gradients previously observed in many dense cores actually originate from
large-scale turbulence or convergent flow compression instead of rigid-body
rotation. We also note that there are targets in this study with their
star-forming disks nearly perpendicular to the local velocity gradients, which,
assuming the velocity gradient represents the direction of rotation, is
opposite to what is described by the classical theory of star formation. This
provides important insight on the transport of angular momentum within
star-forming cores, which is a critical topic on studying protostellar disk
formation.
