The XMM Cluster Survey: forecasting cosmological and cluster scalingrelation parameter constraints
Abstract
We forecast the constraints on the values of σ_{8},Ω_{m} and cluster scalingrelation parameters which we expect to obtain from the XMM Cluster Survey (XCS). We assume a flat Λ cold dark matter Universe and perform a Monte Carlo Markov Chain analysis of the evolution of the number density of galaxy clusters that takes into account a detailed simulated selection function. Comparing our current observed number of clusters shows good agreement with predictions. We determine the expected degradation of the constraints as a result of selfcalibrating the luminositytemperature relation (with scatter), including temperature measurement errors, and relying on photometric methods for the estimation of galaxy cluster redshifts. We examine the effects of systematic errors in scaling relation and measurement error assumptions. Using only (T, z) selfcalibration, we expect to measure Ω_{m} to +/0.03 (and Ω_{Λ} to the same accuracy assuming flatness), and σ_{8} to +/0.05, also constraining the normalization and slope of the luminositytemperature relation to +/6 and +/13 per cent (at 1σ), respectively, in the process. Selfcalibration fails to jointly constrain the scatter and redshift evolution of the luminositytemperature relation significantly. Additional archival and/or followup data will improve on this. We do not expect measurement errors or imperfect knowledge of their distribution to degrade constraints significantly. Scalingrelation systematics can easily lead to cosmological constraints 2σ or more away from the fiducial model. Our treatment is the first exact treatment to this level of detail, and introduces a new `smoothed ML' (Maximum Likelihood) estimate of expected constraints.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2009
 DOI:
 10.1111/j.13652966.2009.14923.x
 arXiv:
 arXiv:0802.4462
 Bibcode:
 2009MNRAS.397..577S
 Keywords:

 methods: statistical;
 galaxies: clusters: general;
 cosmological parameters;
 cosmology: observations;
 cosmology: theory;
 Xrays: galaxies: clusters;
 Astrophysics
 EPrint:
 28 pages, 17 figures. Revised version, as accepted for publication in MNRAS. Highresolution figures available at http://xcshome.org (under "Publications")