Robustness of H0 determination at intermediate redshifts

The most recent Hubble constant (H0) estimates from local methods (z ≪ 1), H0 = 73.8 ± 2.4 km s−1 Mpc−1, and the one from high redshifts, H0 = 67.3 ± 1.2 km s−1 Mpc−1, are discrepant at 2.4σ confidence level. Within this context, Lima & Cunha (LC) derived a new determination of H0 using four cosmic probes at intermediate redshifts (0.1 < z < 1.8) based on the so-called flat ΛCDM model. They obtained H0 = 74.1 ± 2.2 km s−1 Mpc−1, in full agreement with local measurements. In this Letter, we explore the robustness of the LC result searching for systematic errors and its dependence from the cosmological model used. We find that the H0 value from this joint analysis is very weakly dependent on the underlying cosmological model, but the morphology adopted to infer the distance to galaxy clusters changes the result sizeably, being the main source of systematic errors. Therefore, a better understanding of the cluster morphology is paramount to transform this method into a powerful cross-check for H0.