Modelling the rotational curves of spiral galaxies with a scalar field

TL;DR

This paper introduces an improved scalar field model for spiral galaxy rotation curves, emphasizing dark matter coupling, which allows for a universal potential and better fits to observed data, revealing new correlations.

Contribution

The model is refined to focus on dark matter coupling, enabling a universal potential applicable to all galaxies and improved rotation curve fits.

Findings

Enhanced fit to spiral galaxy rotation curves.

Establishment of new correlations in galaxy dynamics.

Potential for a universal scalar field model.

Abstract

In a previous work (Mbelek 2001), we modelled the rotation curves (RC) of spiral galaxies by including in the equation of motion of the stars the dynamical terms from an external real self-interacting scalar field, $\psi$, minimally coupled to gravity and which respects the equivalence principle in the weak fields and low velocity approximation. This model appeared to have three free parameters : the turnover radius, $r_{0}$, the maximum tangential velocity, $v_{\theta max} = v_{\theta}(r_{0})$, plus a strictly positive integer, $n$. Here, we propose a new improved version where the coupling of the $\psi$-field to dark matter is emphasized at the expense of its self-interaction. This reformulation presents the very advantageous possibility that the same potential is used for all galaxies. Using at the same time a quasi-isothermal dark matter density and the scalar field helps to better fit the RC of spiral galaxies. In addition, new correlations are established.