Internal kinematics of dwarf galaxies orbitally moving in ultralight dark matter

TL;DR

This paper investigates how ultralight dark matter influences the internal motion and oscillations of dwarf galaxies orbiting the Milky Way, focusing on the effects of gravitational and dynamical friction torques.

Contribution

It introduces a model for dwarf galaxy internal kinematics considering ultralight dark matter and analyzes the resulting oscillations and torques affecting their dynamics.

Findings

Dynamical friction torque impacts dwarf galaxy internal motion.

Oscillations caused by tidal torque are characterized.

Frequencies and periods of oscillations are calculated.

Abstract

For dwarf galaxies modeled as deformed Plummer spheres and orbitally moving in ultralight dark matter halo of the Milky Way, the torque induced by the dynamical friction force is determined. The impact of this torque, as well as the torque produced by the gravitational force of the Milky Way, on the internal kinematics of dwarf galaxies is studied. Possible oscillations of dwarf galaxies caused by the tidal torque and misalignment of dwarf galaxies with respect to their equilibrium position are investigated and the corresponding frequencies and periods of oscillations are found.