Cosmography, Decelerating Past, and Cosmological Models: Learning the Bayesian Way

Abstract

In this paper, using a significantly improved version of the model-independent, cosmographic approach to cosmology (John, M. V. 2004, ApJ, 614, 1), we address an important question: Was there a decelerating past for the universe? To answer this, the Bayes's probability theory is employed, which is the most appropriate tool for quantifying our knowledge when it changes through the acquisition of new data. The cosmographic approach helps to sort out the models in which the universe was always accelerating from those in which it decelerated for at least some time in the period of interest. Bayesian model comparison technique is used to discriminate these rival hypotheses with the aid of recent releases of supernova data. We also attempt to provide and improve another example of Bayesian model comparison, performed between some Friedmann models, using the same data. Our conclusion, which is consistent with other approaches, is that the apparent magnitude-redshift data alone cannot discriminate these competing hypotheses. We also argue that the lessons learnt using Bayesian theory are extremely valuable to avoid frequent U-turns in cosmology.

Accepted for publication in The Astrophysical Journal (ApJ)

Cited by in corpus (23)

• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Observational constraints on dark energy with generalized equations of state
• Extended Gravity Cosmography
• Cosmography of f(R) gravity
• Cosmic dynamics in the era of Extremely Large Telescopes
• What Do We Really Know About Cosmic Acceleration?
• Comprehensive cosmographic analysis by Markov Chain Method
• AIC, BIC, Bayesian evidence against the interacting dark energy model
• $R_h=ct$ and the eternal coasting cosmological model
• How strong is the evidence for accelerated expansion?
• Modeling Transit Dark Energy in $f(R,L_m)$-gravity
• Model- and calibration-independent test of cosmic acceleration
• Transit String Dark Energy Models in $f(Q)$ Gravity
• Cosmography and large scale structure by f(R) gravity: new results
• {\it Gauging} the cosmic acceleration with recent type Ia supernovae data sets
• Cosmographic Footprints of Dynamical Dark Energy
• Bayesian analysis of bulk viscous matter dominated universe
• Cosmological evolution with quadratic gravity and nonideal fluids
• Searching for gravitationally lensed gamma-ray bursts with their afterglows
• Exact Classical Correspondence in Quantum Cosmology
• Bayesian analysis of running holographic Ricci dark energy
• Bayesian model-independent evaluation of expansion rates of the universe
• Bouncing and coasting universe with exact quantum-classical correspondence