Model-Independent Determination of the Cosmic Growth Factor

Understand

Since the discovery of the accelerated cosmic expansion, one of the most important tasks in observational cosmology is to determine the nature of the dark energy.

• We should build our understanding on a minimum of assumptions in order to avoid biases from assumed cosmological models.
• The two most important functions describing the evolution of the universe and its structures are the expansion function E(a) and the linear growth factor D_+(a).
• The expansion function has been determined in previous papers in a model-independent way using distance moduli to type-Ia supernovae and assuming only a metric theory of gravity, spatial isotropy and homogeneity.