Shadow, acoustic redshift, and transfer observables of Lorentz-violating rotating acoustic black holes

Abstract

We develop an impact-parameter-resolved transfer analysis for the rotating acoustic black hole with Lorentz symmetry violation. The background is the $(2+1)$-dimensional Lorentz-violating draining-bathtub geometry, where the draining parameter $A$ fixes the sonic horizon, the circulation parameter $B$ controls rotation, and the Lorentz-breaking parameter $α$ deforms the effective acoustic metric. We derive the null-ray equations, the critical-impact-parameter conditions, the acoustic shadow interval, and the redshift transfer factor. We then formulate an intensity-transfer prescription for thin rings and extended disks that accounts for source emissivity, emitter motion, finite source width, and detector convolution. The resulting observables form a hierarchy: the shadow width probes Lorentz-violating broadening, the shadow centroid traces rotation, the left-right acoustic-redshift asymmetry tests branch-dependent Doppler and frame-dragging effects, and the integrated flux asymmetry measures their imprint on the observed intensity. We also construct synthetic two-dimensional acoustic screen maps, showing that the $(2+1)$-dimensional capture interval is naturally represented as a vertical strip whose displacement and brightness imbalance encode the combined effects of $B$ and $α$. We focus on the exterior-regular regime $α\geq0$, with $α=0$ retained as the Lorentz-symmetric benchmark.