Implications of a time-varying Galactic potential for determinations of the dynamical surface density

Understand

Recent studies have shown that the passage of a massive satellite through the disk of a spiral galaxy can induce vertical wobbles in the disk and produce features such as in-plane rings and phase-space spirals.

• Here we analyze a high-resolution N-body simulation of a live stellar disk perturbed by the recent passage of a massive dwarf galaxy that induces such perturbations.
• We study the implications of the phase-space structures for the estimate of the matter density through traditional Jeans modelling.
• The dwarf satellite excites rapid time-variations in the potential, leading to a significant bias of the local matter surface density determined through such a method.