Shadows of black holes in dynamical Chern-Simons modified gravity

Abstract

We revisit and extend the study of null geodesics around a slowly rotating black hole in Chern-Simons modified gravity. We employ the Hamilton-Jacobi formalism to derive the equations for the shadow profile and determine its shape. We compare our results with numerical ray tracing, finding good agreement within the validity of our approximations for slow rotation and small Chern-Simons coupling. We forecast constraints on the model parameters using the uncertainty in EHT data for the observed shadow of SgrA* as a reference.