Dynamical Friction due to fuzzy dark matter on satellites described by axisymmetric logarithmic potentials

TL;DR

This study investigates how fuzzy dark matter, with wave-like properties on galactic scales, affects the dynamical friction experienced by non-spherical satellites, revealing shape-dependent variations in drag and timescales comparable to the universe's age.

Contribution

The paper presents simulations of dynamical friction on non-spherical satellites in fuzzy dark matter halos, highlighting the impact of shape and orientation on drag and wake formation.

Findings

Wakes differ qualitatively from spherical cases.

Drag can vary by a factor of 5 based on shape and motion.

Friction timescale is comparable to the Hubble time.

Abstract

A plausible dark matter candidate is an ultralight bosonic particle referred to as fuzzy dark matter. The equivalent mass-energy of the fuzzy dark matter boson is $\sim 10^{-22}$eV and has a corresponding de Broglie wavelength of kiloparsec scale, thus exhibiting wave behaviour in scales comparable to a galactic core, which could not appear in conventional cold dark matter models. The presence of fuzzy dark matter in galactic clusters will impact the motion of their members through dynamical friction. In this work, we present simulations of the dynamical friction on satellites traversing an initially uniform fuzzy dark matter halo. We focus on the satellites whose shapes are beyond spherical symmetry described by ellipsoidal and logarithmic potentials. We find that the wakes created on the fuzzy dark matter halo due to the passage of such satellites are qualitatively different from those generated by spherically symmetric ones. Furthermore, we quantify the dynamical friction coefficient for such systems, finding that the same satellite may experience a drag differing by a factor of $5$ depending on its ellipticity and the direction of motion. Finally, we find that the dynamical friction time-scale is close to Hubble time, assuming a satellite of $10^{11}$M$_{\odot}$ traversing at $10^{3}$km/s a FDM halo whose mean density is $\sim 10^6$M$_{\odot}$kpc$^{-3}$.