Magnetic Fields in Blazar Pc-scale Jets - Possible connection to Spin Rates of Black holes ?

TL;DR

This paper investigates how the magnetic field geometry in blazar jets correlates with black hole spin rates, suggesting that higher spins influence jet properties and magnetic field orientation.

Contribution

It proposes a connection between black hole spin rates and magnetic field geometry differences in various blazar classes based on observational data.

Findings

HPQ jets have predominantly transverse magnetic fields.

LPRQ jets tend to display longitudinal magnetic fields.

Higher black hole spins may explain differences in jet power and magnetic field orientation.

Abstract

We re-examine the differences observed in the pc-scale magnetic field geometry of high and low optical polarization Quasars (HPQs, LPRQs) using the MOJAVE sample. We find that, as previously reported, HPQ jets exhibit predominantly transverse B fields while LPRQ jets tend to display longitudinal B fields. We attempt to understand these results along with the different B field geometry observed in the low and high energy peaked BL Lacs (LBLs, HBLs) using a simple picture wherein the spinning central black holes in these AGNs influence the speed and strength of the jet components (spine, sheath). Higher spin rates in HPQs compared to LPRQs and LBLs compared to HBLs could explain the different total radio powers, VLBI jet speeds, and the observed B field geometry in these AGN classes.