Extremes of the jet-accretion power relation of blazars, as explored by NuSTAR

TL;DR

This study uses NuSTAR and Swift/XRT observations to analyze the extreme jet and accretion power in high-redshift blazars, revealing their variability and placing them at the extreme end of the jet-accretion relation.

Contribution

It demonstrates the importance of hard X-ray observations in studying powerful high-redshift blazars and extends the jet-accretion power relation to the most luminous sources.

Findings

NuSTAR effectively probes variability in high-redshift blazars.

The studied blazars have the most luminous accretion disks and powerful jets.

They occupy the extreme end of the jet-accretion relation.

Abstract

Hard X-ray observations are crucial to study the non-thermal jet emission from high-redshift, powerful blazars. We observed two bright z>2 flat spectrum radio quasars (FSRQs) in hard X-rays to explore the details of their relativistic jets and their possible variability. S5 0014+81 (at z=3.366) and B0222+185 (at z=2.690) have been observed twice by the Nuclear Spectroscopic Telescope Array (NuSTAR) simultaneously with Swift/XRT, showing different variability behaviours. We found that NuSTAR is instrumental to explore the variability of powerful high-redshift blazars, even when no gamma-ray emission is detected. The two sources have proven to have respectively the most luminous accretion disk and the most powerful jet among known blazars. Thanks to these properties, they are located at the extreme end of the jet-accretion disk relation previously found for gamma-ray detected blazars, to which they are consistent.