Kinematical Conformal Cosmology: fundamental parameters from astrophysical observations

Abstract

We continue our presentation of an alternative cosmology based on conformal gravity, following our kinematical approach introduced in a recent paper. In line with the assumptions of our model, which proposes a closed-form expression for the cosmic scale factor R(t), we first revise the Hubble and deceleration parameters and also introduce modified cosmological distances, analyzing in particular the case of the luminosity distance. Our kinematical conformal cosmology is then able to explain the anomalous acceleration of the Pioneer spacecraft, as due to a local region of gravitational blueshift. From the reported values of the Pioneer anomaly we also compute the current value of our first fundamental parameter, gamma_{0} = 1.94 x 10^{-28} cm^{-1}, in line with the original estimate by P. Mannheim of this quantity. Our second fundamental parameter, delta_{0} = 3.83 x 10^{-5}, interpreted as the current value of a cosmological time variable, is derived from a detailed fitting of type Ia Supernovae "gold-silver" data, producing Hubble plots of the same quality of those obtained by standard cosmology, but without requiring any dark matter or dark energy contribution. If further experiments will confirm the presence of an anomalous frequency blueshift in the outer region of the Solar System, as described by our model, kinematical conformal cosmology might become a viable alternative to standard cosmological theories.