Tidal disruption of fuzzy dark matter subhalo cores

TL;DR

This paper investigates how fuzzy dark matter subhalo cores are tidally disrupted through simulations, revealing a runaway mass loss process, core deformation, and providing estimates for core survival based on particle mass and observed satellite galaxies.

Contribution

It introduces a detailed simulation-based analysis of tidal disruption in fuzzy dark matter cores, highlighting unique dynamical behaviors and survival thresholds.

Findings

Tidal stripping causes cores to relax into less compact states.

Runaway disruption occurs once core density drops below a threshold.

Survival of cores depends on FDM particle mass and orbital dynamics.

Abstract

We study tidal stripping of fuzzy dark matter (FDM) subhalo cores using simulations of the Schr\"{o}dinger-Poisson equations and analyze the dynamics of tidal disruption, highlighting the differences with standard cold dark matter. Mass loss outside of the tidal radius forces the core to relax into a less compact configuration, lowering the tidal radius. As the characteristic radius of a solitonic core scales inversely with its mass, tidal stripping results in a runaway effect and rapid tidal disruption of the core once its central density drops below $4.5$ times the average density of the host within the orbital radius. Additionally, we find that the core is deformed into a tidally locked ellipsoid with increasing eccentricities until it is completely disrupted. Using the core mass loss rate, we compute the minimum mass of cores that can survive several orbits for different FDM particle masses and compare it with observed masses of satellite galaxies in the Milky Way.