Understanding the Radial Acceleration Relation of Dwarf Galaxies with Emergent Gravity

TL;DR

This study tests Verlinde's emergent gravity theory against the radial acceleration data of 30 dwarf galaxies, finding it can explain their dynamics without dark matter, unlike MOND which requires new functions.

Contribution

It extends previous work on spiral galaxies to dwarf galaxies, demonstrating emergent gravity's potential to explain galaxy kinematics across different mass scales.

Findings

Emergent gravity matches observed accelerations within uncertainties.

Dark matter is not needed to explain dwarf galaxy dynamics under emergent gravity.

Contrasts with MOND, which requires new interpolating functions for dwarfs.

Abstract

We examine whether the radial acceleration relation (RAR) of dwarf galaxies can be explained by Verlinde's emergent gravity. This is the extension of arXiv:2206.11685v3, which examines the RAR of typical spiral galaxies, to less massive systems. To do this, we compile the line-of-sight velocity dispersion profiles of 30 dwarf galaxies in the Local Group from the literature. We then calculate the expected gravitational acceleration from the stellar component in the framework of the emergent gravity, and compare it with that from observations. The calculated acceleration with the emergent gravity under the assumption of a quasi-de Sitter universe agrees with the observed one within the uncertainty. Our results suggest that the emergent gravity can explain the kinematics of galaxies without introducing dark matter, even for less massive galaxies where dark matter is expected to dominate. This sharply contrasts with MOND, where a new interpolating function has to be introduced for dwarf galaxies to explain their kinematics without dark matter.