Gravitational Theory of Cosmology, Galaxies and Galaxy Clusters

TL;DR

This paper presents a modified gravity theory that extends general relativity with additional fields, successfully explaining cosmological phenomena and galaxy dynamics without requiring dark matter, aligning with Planck data.

Contribution

The paper introduces a modified gravitational theory (MOG) with extra degrees of freedom that accounts for cosmological and galactic observations without dark matter, matching Planck data.

Findings

MOG fits CMB power spectrum, polarization, and lensing data.

MOG explains galaxy rotation curves and cluster dynamics without dark matter.

The theory aligns with Planck cosmological parameters.

Abstract

A modified gravitational theory explains early universe and late time cosmology, galaxy and galaxy cluster dynamics. The modified gravity (MOG) theory extends general relativity (GR) by three extra degrees of freedom: a scalar field $G$, enhancing the strength of the Newtonian gravitational constant $G_N$, a gravitational, spin 1 vector graviton field $\phi_\mu$, and the effective mass $\mu$ of the ultralight spin 1 graviton. For $t < t_{\rm rec}$, where $t_{\rm rec}$ denotes the time of recombination and re-ionization, the density of the vector graviton $\rho_\phi > \rho_b$, where $\rho_b$ is the density of baryons, while for $t > t_{\rm rec}$ we have $\rho_b > \rho_\phi$. The matter density is parameterized by $\Omega_M=\Omega_b+\Omega_\phi+\Omega_r$ where $\Omega_r=\Omega_\gamma+\Omega_\nu$. For the cosmological parameter values obtained by the Planck Collaboration, the CMB acoustical oscillation power spectrum, polarization and lensing data can be fitted as in the $\Lambda$CDM model. When the baryon density $\rho_b$ dominates the late time universe, MOG explains galaxy rotation curves, the dynamics of galaxy clusters, galaxy lensing and the galaxy clusters matter power spectrum without dominant dark matter.