محمد ملک جانی

In this talk, I will introduce the cosmography approach as a model independent method to reconstruct the Hubble expansion rate of the Universe. We first show that the cosmography method based on the Taylor expansion cannot be employed up to high redshifts z=5 where we can observe the distant quasars. Indeed, due to big error truncation of the Taylor expansion, we encounter to the fake tension between the cosmographic parameters of the standard model of cosmology and those of the cosmography approach. We mention that this tension does not appear at lower redshifts z=2 where we observe the SNIa objects. Investigating the cosmography method at higher redshifts than z=2, I will introduce the PADE expansion as a rational approximation and use it instead of Taylor series. We will see that in this case there is no tension between cosmographic parameters of the standard model and those of the cosmography approach.