Cluster science from ROSAT to eROSITA

TL;DR

This paper discusses how galaxy clusters serve as cosmological probes, reviews constraints from ROSAT data, and predicts the enhanced capabilities of the upcoming eROSITA survey for cosmological studies.

Contribution

It provides an analysis of ROSAT cluster data for cosmological constraints and forecasts the improved potential of the eROSITA survey for future research.

Findings

ROSAT data constrains cosmological parameters.

eROSITA will increase survey capabilities by two orders of magnitude.

eROSITA will extend redshift range for galaxy cluster studies.

Abstract

Galaxy clusters are one of the important cosmological probes to test the consistency of the observable structure and evolution of our Universe with the predictions of specific cosmological models. We use results from our analysis of the X-ray flux-limited REFLEX cluster sample from the ROSAT All-Sky Survey to illustrate the constraints on cosmological parameters that can be achieved with this approach. The upcoming eROSITA project of the Spektrum-Roentgen-Gamma mission will increase these capabilities by two orders of magnitude and importantly also increase the redshift range of such studies. We use the projected instrument performance to make predictions on the scope of the eROSITA survey and the potential of its exploitation.