The innermost regions of the jet in NRAO 150. Wobbling or internal rotation?

TL;DR

This study uses high-resolution VLBI observations to analyze the inner jet dynamics of NRAO 150, proposing a helical motion model to explain observed jet wobbling and rotation.

Contribution

It introduces a new helical motion scenario for jet component rotation, extending previous interpretations with detailed VLBA data from 2006 to 2009.

Findings

Jet wobbling is consistent with internal helical motion.

The proposed model explains the observed jet position angle rotation.

VLBI data supports the internal rotation hypothesis.

Abstract

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.