On Filaments, Prolate Halos and Rotation Curves

TL;DR

This paper introduces a geometrical mechanism involving filaments and elongated halos to explain the flattening of galactic rotation curves, fitting observational data and suggesting elongated mass distributions in galaxies.

Contribution

It proposes a new geometrical model for rotation curve flattening using filaments and elongated halos, and demonstrates improved fits to data compared to traditional dark matter profiles.

Findings

Filament presence improves fit quality for rotation curves.

Elongated dark matter halos have a lesser impact on fits.

Results suggest elongated mass distributions in some galaxies.

Abstract

We propose a simple geometrical mechanism for the flattening of galactic rotation curves, the local compression of field lines around their planes induced either by the presence of thin string-like objects at the centers of galaxies or by elongated dark-matter halos, and elaborate on its possible role in Nature. We fit 83 rotation curves from the SPARC database with logarithmic potentials produced by a thin "wire" at the origin and then, after selecting 2 galaxies that yield the most interesting fits, analyze them with an alternative model, deformed versions of two popular models of dark-matter halos. Our conclusion is that the presence of a filament clearly improves the fit quality in a number of cases, while bulged dark matter profiles have a lesser effect. If taken at face value, these results would imply the presence of elongated mass distributions away from the galactic plane in a number of galaxies, and may also have some indirect impact on the controversy between cold dark matter (CDM), self-interacting dark matter (SiDM), and modified Newtonian dynamics (MOND).