A method for obtaining cosmological models consistency relations and Gaussian Processes testing

Abstract

In the present work, we apply consistency relation tests to several cosmological models, including the flat and non-flat ΛCDM models, as well as the flat XCDM model. The analysis uses a non-parametric Gaussian Processes method to reconstruct various cosmological quantities of interest, such as the Hubble parameter H(z) and its derivatives from H(z) data, as well as the comoving distance and its derivatives from SNe Ia data. We construct consistency relations from these quantities which should be valid only in the context of each model and test them with the current data. We were able to find a general method of constructing such consistency relations in the context of H(z) reconstruction. In the case of comoving distance reconstruction, there were not a general method of constructing such relations and this work had to write an specific consistency relation for each model. From H(z) data, we have analyzed consistency relations for all the three above mentioned models, while for SNe Ia data we have analyzed consistency relations only for flat and non-flat ΛCDM models. Concerning the flat ΛCDM model, some inconsistency was found, at more than 2σ c.l., with the H(z) data in the interval 1.8 ≲ z ≲ 2.4, while the other models were all consistent at this c.l. Concerning the SNe Ia data, the flat ΛCDM model was consistent in the 0 < z < 2.5 interval, at 1σ c.l., while the nonflat ΛCDM model was consistent in the same interval, at 2σ c.l.