MOND-like behavior in the Dirac-Milne universe -- Flat rotation curves and mass/velocity relations in galaxies and clusters

TL;DR

This paper demonstrates that the Dirac-Milne universe naturally produces flat galaxy rotation curves, Tully-Fisher and Faber-Jackson relations, and mimics MOND-like behavior, offering an alternative explanation to dark matter and dark energy.

Contribution

It introduces the Dirac-Milne cosmology as a matter-antimatter symmetric universe that reproduces key galactic dynamics and gravitational effects similar to MOND, with novel simulation results.

Findings

Rotation curves are flat beyond 3 virial radii.

A Tully-Fisher relation with exponent ~3 is satisfied.

The model reproduces a MOND-like additional surface gravity.

Abstract

We show that in the Dirac-Milne universe (a matter-antimatter symmetric universe where the two components repel each other), rotation curves are generically flat beyond the characteristic distance of about 3 virial radii, and that a Tully-Fisher relation with exponent $\approx 3$ is satisfied. Using 3D simulations with a modified version of the RAMSES code, we show that the Dirac-Milne cosmology presents a Faber-Jackson relation with a very small scatter and an exponent equal to $\approx 3$ between the mass and the velocity dispersion. We also show that the mass derived from the rotation curves assuming Newtonian gravity is systematically overestimated compared to the mass really present. We also show that the Dirac-Milne universe, featuring a polarization between its matter and antimatter components, presents a behavior similar to that of MOND (Modified Newtonian Dynamics), characterized by an additional surface gravity compared to the Newtonian case. We show that in the Dirac-Milne universe, at the present epoch, the intensity of the additional gravitational field $g_{am}$ due to the presence of clouds of antimatter is of the order of a few $10^{-11}$ m/s$^2$, similar to the characteristic acceleration of MOND. We study the evolution of this additional acceleration $g_{am}$ and show that it depends on the redshift, and is therefore not a fundamental constant. Combined with its known concordance properties on SNIa luminosity distance, age, nucleosynthesis and structure formation, the Dirac-Milne cosmology may then represent an interesting alternative to the $\Lambda$CDM, MOND, and other scenarios for explaining the Dark Matter and Dark Energy conundrum.