Annu. Rev. Astron. Astrophys. 2011. 49:409-470 Copyright © 2011 by Annual Reviews. All rights reserved

8. CONCLUSIONS

Our article has summarized the status of cluster cosmology and the methods used to extract cosmological information from galaxy cluster observations. These methods have been applied successfully to samples of tens to thousands of massive clusters. Much of this work has been pioneered at X-ray and optical wavelengths, but SZ surveys and gravitational lensing studies are also now poised to play central roles.

The availability of powerful, new cluster surveys will help to address profound mysteries such as the origin of cosmic acceleration, inflation and the nature of gravity. This work will require a multiwavelength approach, combining the strengths of the available techniques for finding clusters, calibrating their masses and obtaining low-scatter mass proxies. The analysis of these data will require dedicated efforts by large teams of researchers. The demands for follow-up observations will be high, and will require the support of time allocation committees.

Building on the progress made, we can expect clusters to remain at the forefront of cosmological work through the next decade. By combining cluster measurements with other, powerful probes such as SNIa, CMB, BAO and cosmic shear, we can be optimistic of having the precision, complementarity and redundancy required to allow robust conclusions to be drawn.

We are grateful to our colleagues for their many valuable insights. In particular, we thank Roger Blandford, Hans Böhringer, Marusa Bradač, Joanne Cohn, Carlos Cunha, Megan Donahue, Harald Ebeling, Andy Fabian, Pat Henry, Dragan Huterer, Andrey Kravtsov, Dan Marrone, Tim McKay, Glenn Morris, Daisuke Nagai, Aaron Roodman, Eduardo Rozo, Robert Schmidt, Tim Schrabback, Neelima Sehgal, Aurora Simionescu, Alexey Vikhlinin, Mark Voit, Anja von der Linden, Risa Wechsler and Norbert Werner. We particularly thank David Rapetti for his detailed input to the material on gravity tests and non-gaussianities. SWA was supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515. AEE acknowledges support from NASA Astrophysics Theory Grant NNX10AF61G. ABM was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by Oak Ridge Associated Universities through a contract with NASA. This research was supported in part by the National Science Foundation under Grant No. NSF PHY05-51164.