Are Galaxy Clusters Suggesting an Accelerating Universe?

TL;DR

This paper presents a new kinematic method using Sunyaev-Zel'dovich effect and X-ray data from galaxy clusters to independently confirm the universe's recent acceleration, without relying on specific gravity theories or supernova data.

Contribution

It introduces a novel, model-independent approach to determine cosmic acceleration using galaxy cluster data, providing evidence for a recent transition to acceleration.

Findings

Universe is currently accelerating.

Transition from deceleration to acceleration is recent.

Method is independent of gravity theories and supernova data.

Abstract

The present cosmic accelerating stage is discussed through a new kinematic method based on the Sunyaev- Zel'dovich effect (SZE) and X-ray surface brightness data from galaxy clusters. By using the SZE/X-ray data from 38 galaxy clusters in the redshift range $0.14 \leq z \leq 0.89 $ [Bonamente et al., Astrop. J. {\bf 647}, 25 (2006)] it is found that the present Universe is accelerating and that the transition from an earlier decelerating to a late time accelerating regime is relatively recent. The ability of the ongoing Planck satellite mission to obtain tighter constraints on the expansion history through SZE/X-ray angular diameters is also discussed. Our results are fully independent on the validity of any metric gravity theory, the possible matter- energy contents filling the Universe, as well as on the SNe Ia Hubble diagram from which the presenting accelerating stage was inferred.