A giant radio jet ejected by an ultramassive black hole in a single-lobed radio galaxy

TL;DR

This paper reports the discovery of an extremely large, highly asymmetric radio jet from an ultramassive black hole, providing new insights into jet dynamics, magnetic fields, and radio lobe formation in active galaxies.

Contribution

It presents the first detailed observation of a giant, single-lobed radio jet from an ultramassive black hole, challenging existing symmetry assumptions in radio galaxy models.

Findings

The jet extends approximately 440 kpc with strong polarization.

No radio lobe detected on the counterjet side.

The jet exhibits a predominantly toroidal magnetic field.

Abstract

We report the discovery of a very unusual, highly asymmetric radio galaxy whose radio jet, the largest yet detected, emits strongly polarized synchrotron radiation and can be traced all the way from the galactic nucleus to the hot spot located ~440 kpc away. This jet emanates from an extremely massive black hole (>10^9 solar mass) and forms a strikingly compact radio lobe. No radio lobe is detected on the side of the counterjet, even though it is similar to the main jet in brightness up to a scale of tens of kiloparsecs. Thus, contrary to the nearly universal trend, the brightness asymmetry in this radio galaxy increases with distance from the nucleus. With several unusual properties, including a predominantly toroidal magnetic field, this Fanaroff-Riley type II megajet is an exceptionally useful laboratory for testing the role of magnetic field in jet stabilization and radio lobe formation.