Threads, Ribbons, and Rings in the Radio Galaxy IC 4296

TL;DR

This study uses high-resolution MeerKAT radio imaging to reveal new morphological features in the galaxy IC 4296, including threads, ribbons, and rings, providing insights into jet dynamics and galaxy orientation.

Contribution

The paper introduces the discovery of new radio features in IC 4296 and interprets their origins and orientation, enhancing understanding of radio galaxy morphology.

Findings

Identification of threads, ribbons, and rings in IC 4296

Jets are inclined at approximately 60 degrees from the line-of-sight

Relics of past jet activity are observed as ribbons

Abstract

The nearby elliptical galaxy IC4296 has produced a large (510 kpc) low-luminosity radio source with typical FR I core/jet/lobe morphology. The unprecedented combination of brightness sensitivity, dynamic range, and angular resolution of a new 1.28 GHz MeerKAT continuum image reveals striking new morphological features which we call threads, ribbons, and rings. The threads are faint narrow emission features originating where helical Kelvin-Helmholtz instabilities disrupt the main radio jets. The ribbons are smooth regions between the jets and the lobes, and they appear to be relics of jets powered by earlier activity that have since come into pressure equilibrium. Vortex rings in the outer portions of the lobes and their backflows indicate that the straight outer jets and ribbons are inclined by $i = 60 \pm 5^\circ$ from the line-of-sight, in agreement with photometric, geometric, and gas-dynamical estimates of inclination angles near the nucleus.