Investigating launching of black hole jets with the combined power of the EVN and the EHT

TL;DR

This study uses high-resolution VLBI observations from EVN and EHT to analyze the magnetic fields, accretion flow, and jet launching mechanisms of the SMBH in 3C84, providing insights into AGN jet formation.

Contribution

It combines multi-frequency VLBI data with simulations to investigate jet launching scenarios and magnetic field structures near the SMBH in 3C84.

Findings

Magnetic field strength and structure in the core region identified.

Observed jet instabilities linked to historical evolution.

High-resolution imaging peered through accretion flow to the SMBH.

Abstract

AGN-launched jets are a crucial element in the study of supermassive black holes (SMBH) and their closest surroundings. The formation of such jets, whether they are launched by magnetic field lines anchored to the accretion disc or directly connected to the black hole's (BH) ergosphere, is the subject of ongoing, extensive research. 3C84, the compact radio source in the central galaxy NGC1275 of the Perseus super-cluster, is a prime laboratory for testing such jet launching scenarios, as well as studying the innermost, sub-parsec AGN structure and jet origin. Very long baseline interferometry (VLBI) offers a unique view into the physical processes in action, in the immediate vicinity of BHs, unparalleled by other observational techniques. With VLBI at short wavelengths particular high angular resolutions are obtained. Utilising such cm and mm-VLBI observations of 3C84 with the European VLBI Network and the Event Horizon Telescope, we study the magnetic field strength and associated accretion flow around its central SMBH. This is possible, as higher frequency VLBI measurements are capable of peering through the accretion flow surrounding the central engine of 3C84, which is known to block the line of sight to the sub-parsec counter-jet via free-free absorption. Furthermore, we study the magnetic field's signature in the core region, as manifested in polarised light. As part of this analysis we compare our observations to relativistic magneto-hydrodynamic simulations. Finally, we investigate the effect of instabilities on the shape of the jet's parsec-scale funnel and try to connect them to its historical evolution.