Odd Radio Circles as Candidate Signatures of Black-Hole-Centric Civilizations

Odd Radio Circles (ORCs) are a recently discovered class of extragalactic radio source characterised by edge-brightened ring morphology at 300–500 kpc projected scale, steep-spectrum synchrotron emission, and the absence of detectable counterparts at optical, infrared, and X-ray wavelengths. The published natural-explanation menu — galaxy mergers, starburst termination shocks, virial shocks, revived radio lobes, end-on AGN jet bubbles, and others — accounts for individual objects but does not unify the catalogue, with per-object tuning required and the field's own assessment being that no simple model can easily explain the observed structure. The recent BH-SETI literature has accumulated detailed theoretical predictions for advanced-civilization signatures around supermassive black holes without confirmed observations matching those predictions. This paper proposes ORCs as candidate signatures of black-hole-centric civilizations in a post-cocoon phase of development, synthesising the parsec-scale Dyson Mind framework of recent workshop literature with the Omega-phase physics of Tipler, and identifying a previously unaddressed gap in the published literature — the outside view of the post-cocoon phase. Specific testable predictions follow, including a host-galaxy age floor, a redshift ceiling near z ~ 1.5, and substructure morphology matching the projection geometry of two perpendicular shell systems aligned with the Kerr-metric privileged axes. Submitted to Acta Astronautica, May 2026