MeerKAT uncovers the physics of an odd radio circle
R. P. Norris, J. D. Collier, Roland M. Crocker, Ian Heywood, Peter J. Macgregor, L. Rudnick, Stanislav S. Shabala, H. Andernach, Elisabete da Cunha, Jayanne English, M. D. Filipović, B. Koribalski, Kieran Luken, A. S. G. Robotham, Srikrishna Sekhar, Jessica E Thorne, Tessa Vernstrom
Abstract
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 μJy/beam). In addition to the new images, which reveal a complex internal structure consisting of multiple arcs, we also present polarization and spectral index maps. Based on these new data, we consider potential mechanisms that may generate the ORCs.