The innermost regions of the jet in NRAO 150. Wobbling or internal
  rotation?
  NRAO 150 is a very bright millimeter to radio quasar at redshift $z$=1.52 for
which ultra-high-resolution VLBI monitoring has revealed a counter-clockwise
jet-position-angle wobbling at an angular speed $\sim11^{\circ}$/yr in the
innermost regions of the jet. In this paper we present new total and linearly
polarized VLBA images at 43 GHz extending previous studies to cover the
evolution of the jet in NRAO 150 between 2006 and early 2009. We propose a new
scenario to explain the counter-clockwise rotation of the jet position angle
based on a helical motion of the components in a jet viewed faced-on. This
alternative scenario is compatible with the interpretation suggested in
previous works once the indetermination of the absolute position of the
self-calibrated VLBI images is taken into account. Fitting of the jet
components motion to a simple internal rotation kinematical model shows that
this scenario is a likely alternative explanation for the behavior of the
innermost regions in the jet of NRAO 150.
