MOND and the Galaxies

TL;DR

This paper reviews galaxy formation and dynamics under MOND, comparing it to dark matter models, and discusses how different predictions can help discriminate between theories and constrain their parameters.

Contribution

It provides a comparative analysis of galaxy behavior in MOND versus Newtonian dark matter models, highlighting unique predictions and observational constraints.

Findings

Galaxy instabilities differ between theories.

Bar frequency observations constrain models.

Merger rates are sensitive tests for theories.

Abstract

We review galaxy formation and dynamics under the MOND hypothesis of modified gravity, and compare to similar galaxies in Newtonian dynamics with dark matter. The aim is to find peculiar predictions both to discriminate between various hypotheses, and to make the theory progress through different constraints, touching the interpolation function, or the fundamental acceleration scale. Galaxy instabilities, forming bars and bulges at longer term, evolve differently in the various theories, and help to bring constraints, together with the observations of bar frequency. Dynamical friction and the predicted merger rate could be a sensitive test of theories. The different scenarios of galaxy formation are compared within the various theories and observations.