Testing Weyl Gravity at Galactic and Extra-galactic Scales

TL;DR

This paper tests Weyl conformal gravity as an alternative to general relativity by analyzing galactic rotation curves, globular cluster velocities, and galaxy cluster acceleration, finding it consistent with observations without dark matter.

Contribution

It demonstrates that Weyl gravity can explain galactic and extra-galactic dynamics without dark matter, using observational data from the Milky Way, globular clusters, and galaxy clusters.

Findings

Weyl gravity matches Milky Way rotation curves without dark matter.

Predictions encompass measurement uncertainties in baryonic models.

Weyl gravity accounts for acceleration in galaxy cluster Abell 1689.

Abstract

We examine the viability of Weyl conformal gravity as an alternative to the general theory of relativity. By using the extended rotation curve of the Milky Way and velocity dispersions of four globular clusters, we show that Weyl gravity predictions without resorting to dark matter comply with observations at the galactic scale. For the Milky Way, we demonstrate that the uncertainty in baryonic modelling results a bracket of possible rotational velocities which well encompasses the diversity in rotation curve construction. Such diversity generally arises from differences in measurements of velocity anisotropy parameter, and the circular speed and Galactocentric distance of the Sun. Furthermore, we explore the ability of Weyl gravity to account for the inferred acceleration of Abell cluster 1689.