The Highly Self-Absorbed Blazar, PKS\,1351$-$018

TL;DR

This paper studies the unique dual nature of the highly luminous, steady synchrotron source PKS 1351-018, revealing a compact, young, powerful radio jet coexisting with blazar-like variability and high-velocity winds.

Contribution

It provides detailed multi-epoch radio and gamma-ray observations of PKS 1351-018, characterizing its steady and flaring behaviors, jet structure, and environment, highlighting its rare properties as a young, powerful, and nearly aligned blazar.

Findings

PKS 1351-018 is extremely luminous and steady over 35 years.

The source hosts a young, powerful radio jet with a deprojected distance of 1-3 kpc.

Evidence of high-velocity, high-ionization winds from the quasar.

Abstract

PKS\,1351$-$018 at a redshift of $z=3.71$ is one of the most luminous, steady synchrotron sources with a luminosity $> 10^{47}$\,erg~s$^{-1}$. The synchrotron luminosity does not seem to vary by more than $\sim 25\%$ over 35 years. 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 yrs. In spite of this steady behavior, two strong $\gamma$-ray flares $\lesssim 10^{49}$\,erg~s$^{-1}$ were detected in 2011 and 2016. There is 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 to 2018. We estimate that a jet with a time averaged power of $(5.2 \pm 3.2) \times 10^{45}$\,erg~s$^{-1}$ terminates in this lobe that is advancing $\gtrsim 0.9 c$ at a deprojected distance of $1-3$\,kpc from the central engine. This is the rare case of a young ($\sim 6000$\,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 form a luminous quasar. The young radio jet appears to experience modest bending as it navigates through the intense quasar environment.