AIC, BIC, Bayesian evidence against the interacting dark energy model

Abstract

Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting $$\Lambda $$ΛCDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative—the $$\Lambda $$ΛCDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam’s principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), $$h(z)$$h(z), baryon acoustic oscillation, the Alcock–Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting $$\Lambda $$ΛCDM model when compared to the $$\Lambda $$ΛCDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the $$\Lambda $$ΛCDM model. Given the weak or almost non-existing support for the interacting $$\Lambda $$ΛCDM model and bearing in mind Occam’s razor we are inclined to reject this model.