Marie Curie fellow at the Niels Bohr Institute

The nozzle shock in tidal disruption events


Part of the stream of debris produced during a tidal disruption event comes back near the black hole on inclined orbital planes, which results in an intersection of its trajectories close to pericenter. We carried out in this paper the first numerical study dedicated to the resulting interaction, which is usually called the "nozzle shock". This is achieved by making use of a two-dimensional simulation that follows the transverse gas evolution inside a given section of the returning stream during its passage at pericenter.The movie below shows the transverse evolution of the gas density during this process in the frame co-moving with the center of mass of the stream element considered. The matter gets strongly compressed in the vertical direction close to pericenter, resulting in the nozzle shock that causes this gas to bounce back and keep expanding as it moves away from the black hole.