Simulation of a Compact Object with Outflows Moving Through a Gaseous Background

Understand

A compact object moving relative to surrounding gas accretes material and perturbs the density of gas in its vicinity.

• In the classical picture of Bondi-Hoyle-Lyttleton accretion, the perturbation takes the form of an overdense wake behind the object, which exerts a dynamical friction drag.
• We use hydrodynamic simulations to investigate how the accretion rate and strength of dynamical friction are modified by the presence of outflow from the compact object.
• We show that the destruction of the wake by an outflow reduces dynamical friction, and reverses its sign when the outflow is strong enough, in good quantitative agreement with analytic calculations.