Ionization echoes of past AGN in Green Bean galaxies

Green Bean galaxies represent a short-lived AGN phase, during which extended emission-line structures trace the large-scale responses of the surrounding gas to past active AGN episodes in galaxies at redshifts 0.2-0.6. We present spatially resolved spectroscopic observations of a sample of Green Bean galaxies obtained with long-slit and 3D spectroscopy at the 6-m BTA telescope. Across the sample, we detect a clear spatial decoupling between the current nuclear activity and the extended ionized gas at the distances of ~20-80 kpc, together with a spatial misalignment between radio and ionized gas structures. The central regions typically show weak or low-ionization signatures, while the large-scale gas requires a much higher ionizing output. Our results demonstrate that radiative AGN feedback leaves long-lived, galaxy-scale imprints in the circumgalactic medium that can be detected long after the nucleus has faded. The consistency of these features across multiple objects suggests that extended ionization structures on scales of tens of kiloparsecs provide key constraints on AGN duty cycles and feedback timescales.