Exploring Sourced Carrollian Fluids through Black Holes

Black hole horizons as null surfaces have properties for which one can construct analogies between gravitation and fluid dynamics. The degenerate geometry of the event horizon allows analogies between gravity and Carrollian fluids – an unusual limit of relativistic hydrodynamics in which the speed of light vanishes. We study the dynamics of the black hole horizon under a coupling to a massless scalar field and connect it to Carrollian hydrodynamics with a driving source. Through this setup, we make further observations about the properties of Carrollian fluids.