Dark Matter and MOND successes and degeneracies in reproducing SPARC rotation curves and weak lensing data
Year: 2026
Type: preprint
Abstract: The observed rotation velocities of spiral galaxies at large scales exceed those predicted by their baryonic components, motivating the need for dark matter (DM) or Modified Newtonian Dynamics (MOND). We fit the rotation curves of 147 late-type galaxies from the SPARC database, using a suite of models including Cold Dark Matter (CDM) models with and without baryonic feedback, Warm DM, Fuzzy DM, and MOND. We also combine SPARC kinematics with weak-lensing data to extend the mean rotation curves to ~1 Mpc. On a galaxy-by-galaxy basis, the inner SPARC rotation curves marginally favour CDM models with baryonic feedback, although accounting for the uncertainties in distances and inclinations increases the degeneracy among DM-based models and MOND. All DM models predict host halo masses larger than abundance-matching expectations, with only the CDM model with baryonic feedback reducing the scatter around the mean luminosity-halo mass relation. MOND is able to reproduce the flatness of the mean galactic rotation curves on scales up to 1 Mpc, providing stellar mass-to-light ratios within observational uncertainties. In contrast, all DM models, without the contribution of mass external to the bound halo, struggle to explain the flat rotation curves. The inclusion of the current weak-lensing data tends to favour MOND over DM models, at least at the largest scales. Future observations from BIG-SPARC, the Square Kilometre Array, and most importantly, upcoming weak-lensing surveys such as EUCLID and Rubin will provide more stringent and independent tests of these competing frameworks
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G3114824966, G5789910615
OpenAlex ID: W7223971348