Modified Gravity (MOG) and its test on galaxy clusters

TL;DR

This paper tests the Modified Gravity (MOG) theory against galaxy cluster data, finding that MOG requires additional dark matter-like components to fit observations, challenging its viability as an alternative to dark matter.

Contribution

The study provides new X-ray and lensing data for galaxy clusters A1689 and A1835, critically evaluating MOG's ability to explain cluster observations without dark matter.

Findings

MOG can fit cluster data by adjusting galaxy density profiles.

MOG requires effective dark matter components to match lensing observations.

Gas-only models tend to overestimate lensing effects in MOG.

Abstract

The MOdified Gravity (MOG) theory of J. Moffat assumes a massive vector particle which causes a repulsive contribution to the tensor gravitation. For the galaxy cluster A1689 new data for the X-ray gas and the strong lensing properties are presented. Fits to MOG are possible by adjusting the galaxy density profile. However, this appears to work as an effective dark matter component, posing a serious problem for MOG. New gas and strong lensing data for the cluster A1835 support these conclusions and point at a tendency of the gas-alone to overestimate the lensing effects in MOG theory.