出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：NRAO 530 (also known as 1730-130) is being studied by high-frequency VLBI observations. We investigate the frequency-dependent position shifts of jet components, and the detailed jet kinematics over the last ten years. We find significant position shifts for 3 jet components (component d, e, and f) with a mean shift of −0.15±0.02mas between 22 and 43GHz and detected for the first time a 2-dimensional position shift (component f) indicative of oblique structures. We obtained apparent velocities of 8 jet components with bapp ranging from (2–26) c. Accordingly, we estimated jet physical parameters with a minimum Lorentz factor of 14 and Doppler factors in the range of 14 and 28 (component f). The observed variations in the morphology of NRAO 530 are related to the motion of separate jet components along the jet, with the most pronounced changes occurring near the core. We estimated a position angle swing of 4◦ per year for jet component d. The non-ballistic motion and change of jet orientation makes this source another prominent example of a helical and possibly “swinging/wobbling” jet, such as BL Lac or NRAO150.
