AAS 202nd Meeting, May 2003
Session 23 Observational Probes of Dark Energy
Topical Oral, Tuesday, May 27, 2003, 8:30-10:00am, 10:45am-12:30pm, 2:00-3:30pm and 3:45-5:30pm, 205/206

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[23.03] Studying Dark Energy with Galaxy Cluster Surveys

J. Mohr, S. Majumdar (U. Illinois)

Galaxy cluster surveys provide a powerful means of studying the amount and nature of the dark energy. Cluster surveys are complementary to studies using supernova distance estimates, because the cosmological parameter degeneracies are quite different. The redshift distribution of detected clusters in a deep, large solid angle survey is very sensitive to the dark energy equation of state, but robust constraints require mass--observable relations that connect cluster halo mass to observables such as the X-ray luminosity, Sunyaev-Zel'dovich effect distortion, galaxy light or weak lensing shear. Observed regularity in the cluster population and the application of multiple, independent mass estimators provide evidence that these scaling relations exist in the local and intermediate redshift universe.

Large cluster surveys contain enough information to study the dark energy and solve for these scaling relations and their evolution with redshift. This self--calibrating nature of galaxy cluster surveys provides a level of robustness that is extremely attractive. Cosmological constraints from a survey can be improved by including more than just the redshift distribution. Limited followup of as few as 1% of the surveyed clusters to make detailed mass measurements improves the cosmological constraints. Including constraints on the mass function at each redshift provides additional power in solving for the evolution of the mass--observable relation. An analysis of the clustering of the surveyed clusters provides additional cosmological discriminating power.

There are several planned or proposed cluster surveys that will take place over the next decade. Observational challenges include estimating cluster redshifts and understanding the survey completeness. These challenges vary with wavelength regime, suggesting that multiwavelength surveys provide the most promising avenue for precise galaxy cluster studies of the dark energy.

This work is supported in part by the NASA Long Term Space Astrophysics grant NAG 5-11415.

If you would like more information about this abstract, please follow the link to http://cosmology.astro.uiuc.edu/~jmohr. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: jmohr@uiuc.edu

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