Precessing Jet in the High-Redshift Blazar J0017+8135

TL;DR

This study analyzes over 20 years of VLBI data of the high-redshift quasar J0017+8135, revealing a precessing jet with a 12-year period, enhancing understanding of jet dynamics in distant AGN.

Contribution

It provides the first detailed kinematic model of jet precession in a high-redshift quasar based on extensive long-term VLBI observations.

Findings

Jet exhibits a precession with a 12-year period in the observer's frame.

Long-term VLBI data is crucial for understanding jet behavior in high-redshift AGN.

The jet structure shows systematic positional variations over two decades.

Abstract

The prominent flat-spectrum radio quasar J0017+8135 (S5 0014+81) at z = 3.366 is one of the most luminous active galactic nuclei (AGN) known. Its milliarcsecond-scale radio jet structure has been studied with very long baseline interferometry (VLBI) since the 1980s. The quasar was selected as one of the original defining objects of the International Celestial Reference Frame, but left out from its current second realization (ICRF2) because of systematic long-term positional variations. Here we analyse archival 8.6- and 2.3-GHz VLBI imaging data collected at nearly 100 different epochs during more than 20 years, to obtain information about the kinematics of jet components. Because of the cosmological time dilation, extensive VLBI monitoring data are essential to reveal changes in the jet structure of high-redshift AGN. In the case of J0017+8135, the data can be described with a simple kinematic model of jet precession with a 12-year periodicity in the observer's frame.