Machian Gravity: Modeling Rotation Curves and Radial Acceleration in the SPARC Galaxy Sample

TL;DR

This paper explores Machian Gravity, a five-dimensional theory, to explain galaxy rotation curves without dark matter, fitting observational data from the SPARC galaxy sample and identifying a characteristic acceleration scale.

Contribution

It applies Machian Gravity to real galaxy data, demonstrating its ability to model rotation curves and revealing a variable acceleration scale similar to MOND.

Findings

Successfully fits galaxy rotation curves using MG parameters

Identifies a characteristic acceleration scale around 10^{-8} cm/s^2

Shows the acceleration scale varies between galaxies

Abstract

This paper investigates the potential of Machian Gravity (MG), a five-dimensional theory of gravity, to explain the acceleration law governing rotationally bound systems, in particular spiral galaxies. MG was proposed as a framework capable of accounting for a range of astrophysical and cosmological phenomena -- including galactic rotation curves, mass distributions in galaxy clusters, and cosmic expansion -- without invoking additional dark components. In this study, we apply the MG acceleration law to a large sample of galaxies drawn from the SPARC database. Through a detailed analysis, we determine the optimal MG parameters for each individual galaxy, successfully fitting their observed rotation curves. Similar to Modified Newtonian Dynamics (MOND), our results indicate the existence of a characteristic acceleration scale associated with galactic dynamics, which regulates rotational behavior in the outer regions. Notably, this acceleration scale varies from galaxy to galaxy, but typically remains of order $10^{-8} {\rm cm/s^2}$.