Investigating Dark Matter and MOND Models with Galactic Rotation Curve Data

Understand

We study geometries of galactic rotation curves from Dark Matter (DM) and Modified Newtonian Dynamics (MOND) models in $(g_{\rm bar},g_{\rm tot})$-space ($g2$-space) where $g_{\rm tot}$ is the total centripetal acceleration of matter in the galaxies and $g_{\rm bar}$ is that due to the baryonic (visible) matter assuming Newtonian gravity.

• The $g2$-space geometries of the models and data from the SPARC database are classified and compared in a rescaled $\hat{g}2$-space that reduces systematic uncertainties on galaxy distance, inclination angle and variations in mass to light ratios.
• We find that MOND modified inertia models, frequently used to fit rotation curve data, are disfavoured at more than 5$\sigma$ independent of model details.
• The Bekenstein-Milgrom formulation of MOND modified gravity compares better with data in the analytic approximation we use.