Self-consistent models of triaxial galaxies in MOND gravity

TL;DR

This study demonstrates that self-consistent triaxial galaxy models with cuspy density profiles can exist within MOND gravity, challenging the necessity of dark matter for such structures.

Contribution

It introduces the use of orbit superposition techniques to construct triaxial galaxy models in MOND, showing their viability without dark matter.

Findings

Self-consistent triaxial galaxies exist in MOND for various density concentrations.

Orbit superposition is effective beyond Newtonian gravity.

Triaxial cuspy galaxies may form without Cold Dark Matter.

Abstract

The Bekenstein-Milgrom gravity theory with a modified Poisson equation is tested here for the existence of triaxial equilibrium solutions. Using the non-negative least square method, we show that self-consistent triaxial galaxies exist for baryonic models with a mild density cusp $\rho \sim {\Sigma \over r}$. Self-consistency is achieved for a wide range of central concentrations, $\Sigma \sim 10-1000\mathrm{M_{\odot}pc^{-2}}$, representing low-to-high surface brightness galaxies. Our results demonstrate for the first time that the orbit superposition technique is fruitful for constructing galaxy models beyond Newtonian gravity, and triaxial cuspy galaxies might exist without the help of Cold dark Matter.