Photon rings around warped black holes

The black hole photon ring is a prime target for upcoming space-based VLBI missions seeking to image the fine structure of astrophysical holes. classical Lyapunov exponents corresponding nearly bound null geodesics control quasinormal ringing perturbed as it settles back down equilibrium, and they admit holographic interpretation in terms quantum Ruelle resonances microstate dual Kerr hole. Recent work has identified number emergent symmetries related intricate self-similar ring. Here, we explore this web interrelated phenomena an exactly soluble example that arises approximation near-extremal self-dual warped AdS$_3$ geometry well $\mathsf{SL}(2,\mathbb{R})$ isometries calculable mode (QNM) spectrum. We show explicitly geometric optics reproduces eikonal limit exact QNM spectrum, approximate "near-ring" wavefunctions. are directly conformal symmetry images but distinct from recently discussed equivalence spectrum -- thus context spacetime with putative suggests indeed part hologram.