MeerKAT uncovers the physics of an Odd Radio Circle

TL;DR

This paper presents high-resolution MeerKAT radio images of the first discovered Odd Radio Circle, revealing complex internal structures and providing insights into their possible origins.

Contribution

It offers the first detailed MeerKAT observations of an ORC, uncovering internal structures and polarization features to better understand their physics.

Findings

Revealed complex internal structures with multiple arcs.

Provided polarization and spectral index maps of the ORC.

Suggested potential mechanisms for ORC formation.

Abstract

Odd Radio Circles (ORCs) are recently-discovered faint diffuse circles of radio emission, of unknown cause, surrounding galaxies at moderate redshift ($z ~ 0.2-0.6). Here we present detailed new MeerKAT radio images at 1284 MHz of the first ORC, originally discovered with the Australian Square Kilometre Array Pathfinder, with higher resolution (6 arcsec) and sensitivity (~ 2.4 uJy/bm). In addition to the new images, which reveal a complex internal structure consisting of multiple arcs, we also present polarisation and spectral index maps. Based on these new data, we consider potential mechanisms that may generate the ORCs.