2021ApJ...919...40P

PKS 1351-018 at a redshift of z = 3.71 is one of the most luminous, steady synchrotron sources with a luminosity >10⁴⁷ erg s^–1. The synchrotron luminosity does not seem to have varied by more than ∼25% over 35 yr. In order to appreciate this remarkable behavior, if it were at z = 0.5, it would have a flux density at 15 GHz in a range of 110-137 Jy over 11 yr. In spite of this steady behavior, two strong γ-ray flares <=10⁴⁹ erg s^–1 were detected in 2011 and 2016. There is a blazar-like behavior coexisting with the steady behavior. This study is aimed at elucidating the dual nature of this source. We find that the radio source is extremely compact with a bright core and a steep spectrum secondary component, 12 mas away, that appears to be constant in position and flux density in six epochs from 1995-2018. We estimate that a jet with a time averaged power of (5.2 ± 3.2) x 10⁴⁵ erg s^–1 terminates in this lobe, which is advancing >=0.9c at a deprojected distance of 1-3 kpc from the central engine. This is the rare case of a young (∼6000 yr), very powerful radio source that is viewed a few degrees from the jet axis. We find evidence of a high velocity (4000 km s^–1), high ionization wind emanating from a luminous quasar. The young radio jet appears to experience modest bending as it navigates through the intense quasar environment.