Non-ballistic motion and precessing helical trajectory in quasar NRAO 150

摘要

NRAO 150 is a very special radio quasar in which prominent non-ballistic superluminal motion has been observed in its inner-jet region. We apply model-fittings to the kinematics of the superluminal knots(trajectory, distance from the core and apparent velocity) in terms of a helical precessing jet-nozzle model.Five cases are considered in which the angle between the jet axis and the line of sight is assumed to be 6?,3?, 1?, 0.6? and 0.12?, respectively. It is shown that the superluminal components have intrinsic acceleration in the innermost regions(≤0.2 mas from the core). The phenomenon of precessing nozzle/trajectory can be understood on the basis of relativistic magnetohydrodynamic theories for relativistic jets.