Dynamical friction in ultralight dark matter: Plummer sphere perspective

TL;DR

This paper derives analytic expressions for dynamical friction acting on Plummer sphere globular clusters in ultralight dark matter models, revealing deviations from point mass behavior at large sizes and Mach numbers.

Contribution

It provides the first analytic formulas for dynamical friction on extended Plummer spheres in ultralight dark matter contexts, highlighting size and Mach number effects.

Findings

Dynamical friction force differs from point mass case at large sphere sizes.

Analytic expressions for radial and tangential components are derived.

Significant deviations occur at high Mach numbers and large sphere radii.

Abstract

In models of dark matter composed of feebly interacting ultralight bosons in the state of Bose-Einstein condensate, the dynamical friction force acting on circularly moving globular clusters modelled as Plummer spheres is determined. Analytic expressions for both radial and tangential components of the dynamical friction force are given. We reveal that the dynamical friction force for the Plummer sphere deviates from that for a point probe of the same mass for a significantly large ratio of the Plummer sphere radius to its orbital radius, as well as for large values of the Mach number.