Modeling Dark Matter Halos with Nonlinear Field Theories

TL;DR

This paper models galactic dark matter using a nonlinear scalar field theory coupled with gravity, providing analytical solutions that explain galaxy rotation curves through position-dependent scalar field self-interactions.

Contribution

It introduces a novel nonlinear scalar field model with position-dependent self-interactions that accurately describes galactic rotation curves.

Findings

Analytical solutions for scalar fields in the Newtonian limit.

Model explains rotation curves of dwarf and low surface brightness galaxies.

Self-interaction strength varies with position, vanishing at galaxy edges.

Abstract

In the present work, we adopt a nonlinear scalar field theory coupled to the gravity sector to model galactic dark matter. We found analytical solutions for the scalar field coupled to gravity in the Newtonian limit, assuming an isotropic spacetime and a field potential, with a position dependent form of the superpotential, which entails the nonlinear dynamics of the model with self-interactions. The model introduces a position dependent enhancement of the self-interaction of the scalar fields towards the galaxy center, and while going towards the galaxy border the interaction tends to vanish building a non self-interacting DM scenario. The developed approach is able to provide a reasonable analytical description of the rotation curves in both dwarf and low surface brightness late-type galaxies, with parameters associated with the dynamics of the scalar field.