Exploring the expansion dynamics of the universe from galaxy cluster surveys

TL;DR

This study uses galaxy cluster data to constrain cosmological models, revealing that local measurements of H0 are more consistent with recent observations, and suggests possible evidence for dynamical dark energy at low redshifts.

Contribution

It provides new constraints on H0 and dark energy evolution using galaxy cluster surveys and model-independent methods, highlighting potential late-time dark energy dynamics.

Findings

H0 values align more with local measurements than global ones.

No evidence of dynamical dark energy in the first sample.

Possible phantom-crossing behavior indicating evolving dark energy.

Abstract

To understand the expansion dynamics of the universe from galaxy cluster scales, using the angular diameter distance (ADD) data from two different galaxy cluster surveys, we constrain four cosmological models to explore the underlying value of $H_0$ and employ the model-independent Gaussian Processes to investigate the evolution of the equation of state of dark energy. The ADD data in the X-ray bands consists of two samples covering the redshift ranges [0.023, 0.784] and [0.14, 0.89], respectively. We find that: (i) For these two samples, the obtained values of $H_0$ are more consistent with the recent local observation by Riess et al. than the global measurement by the Plank Collaboration, and the $\Lambda$CDM model is still preferred utilizing the information criterions; (ii) For the first sample, there is no evidence of dynamical dark energy (DDE) at the $2\sigma$ confidence level (CL); (iii) For the second one, the reconstructed equation of state of dark energy exhibits a phantom-crossing behavior in the relatively low redshift range over the $2\sigma$ CL, which gives a hint that the late-time universe may be actually dominated by the DDE from galaxy cluster scales; (iv) By adding a combination of Type Ia Supernovae, cosmic chronometers and Planck-2015 shift parameter and HII galaxy measurements into both ADD samples, the DDE exists evidently over the $2\sigma$ CL.