Cosmological Studies With A Large-Area X-ray Telescope

TL;DR

This paper discusses how the International X-ray Observatory can significantly contribute to cosmology by studying high-redshift galaxy clusters, providing precise measurements of dark energy and cosmic acceleration.

Contribution

It introduces the use of IXO observations combined with lensing follow-up as a novel approach to measure cosmological parameters with high accuracy.

Findings

IXO can measure the perturbation growth factor from z=0-2.

IXO observations can improve constraints on dark energy.

The method offers competitive accuracy with SNIa and BAO studies.

Abstract

A moderate investment of observing time with the International X-ray Observatory to study high-redshift galaxy clusters detected in future large-scale surveys, will provide cosmological measurements of fundamental importance. IXO observations, combined with lensing follow-up, will measure the perturbation growth factor from z=0-2 with an accuracy comparable to, or possibly better than, that expected from observations of cosmic shear with JDEM, and redshift-space distortions with EUCLID. The growth of structure data derived from clusters will significantly improve our knowledge of the dark energy equation of state and will aid in constraining non-GR models for cosmic acceleration. IXO observations of the largest, dynamically relaxed clusters will provide a powerful, independent measurement of the cosmological expansion history using the apparent f_gas(z) trend. Systematic and statistical errors from this technique are competitive with SNIa and BAO studies, making the test extremely useful for improving the accuracy and reliability of the geometric cosmological measurements planned for LSST and JDEM. Only by employing a range of powerful, independent approaches, including those discussed here, can robust answers to puzzles as profound as the origin of cosmic acceleration be expected.