Image Plane Models for AGN Jets at Horizon Scale

Abstract When observed at the highest angular resolution, the central regions of jets driven by active galactic nuclei often exhibit a parabolic geometry and pronounced limb-brightening. In this paper, we present a new parametric model that reproduces these features and integrate it with the previously developed “m-ring” model, which describes the accretion flow onto a supermassive black hole at event-horizon scales. The resulting combined jet–ring model successfully captures the key structures seen in Very Long Baseline Interferometry (VLBI) observations of prototypical sources such as M 87 and Centaurus A. This model is particularly well-suited to support existing ground interferometers such as the Global-Millimeter VLBI Array (GMVA) and the Event Horizon Telescope (EHT) and proposed ground- and space-based VLBI experiments, including the Next-Generation Event Horizon Telescope (ngEHT), the Black Hole Explorer (BHEX) and the Next-Generation Very Large Array (ngVLA), which aim to probe jet launching and collimation by imaging nearby supermassive black holes at event-horizon scales with microarcseconds resolution.