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 $Omega_r=Omega_gamma+Omega_ u$. 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.
تحميل البحث