Abstract
Recently, Risaliti and Lusso [Nat. Astron. 3, 272 (2019)] reported new measurements of the expansion rate of the Universe by constructing the Hubble diagram of 1598 quasars in the redshift range . It is claimed a tension with the standard concordance concerning both the fractionary matter density and the dark energy equation of state parameter standard values. In this work we promote an independent analysis of the same data set using a model-independent estimator for cosmic acceleration. Our results corroborate that the source of such tension can be related to the value with a reasonable indication of a higher value (). On the other hand, we find that the role played by on the claimed tension is weak. We also discuss the use of this estimator as a “quality tool” to test the robustness of Hubble diagrams. We conclude claiming that the quasars data cannot yet be seen as a reliable cosmological tool since they cannot even state the universe experienced an accelerated expansion phase.
- Received 1 December 2019
- Accepted 15 January 2020
DOI:https://doi.org/10.1103/PhysRevD.101.043502
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