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New constraints on σ8 from a joint analysis of stacked gravitational lensing and clustering of galaxy clusters

Journal
Date Issued
2015
Author(s)
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COVONE, GIOVANNI
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CIMATTI, ANDREA
DOI
Description
The authors thank C. Carbone for discussions. The authors acknowledge financial contributions from contracts ASI/INAF n.I/023/12/0 ‘Attività relative alla fase B2/C per la missione Euclid’, PRIN MIUR 2010-2011 ‘The dark Universe and the cosmic evolution of baryons: from current surveys to Euclid’ and PRIN INAF 2012 ‘The Universe in the box: multiscale simulations of cosmic structure’. This work is based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/IRFU, at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France and the University of Hawaii. This research used the facilities of the Canadian Astronomy Data Centre operated by the NRC of Canada with the support of the Canadian Space Agency. CFHTLenS data processing was made possible thanks to significant computing support from the NSERC Research Tools and Instruments grant programme.
Abstract
The joint analysis of clustering and stacked gravitational lensing of galaxy clusters in large surveys can constrain the formation and evolution of structures and the cosmological parameters. On scales outside a few virial radii, the halo bias, b, is linear and the lensing signal is dominated by the correlated distribution of matter around galaxy clusters. We discuss a method to measure the power spectrum amplitude σ8 and b based on a minimal modelling. We considered a sample of ̃120 000 clusters photometrically selected from the Sloan Digital Sky Survey in the redshift range 0.1 < z < 0.6. The autocorrelation was studied through the two-point function of a subsample of ̃70 000 clusters; the matter-halo correlation was derived from the weak lensing signal of the subsample of ̃1200 clusters with Canada-France-Hawaii Telescope Lensing Survey data. We obtained a direct measurement of b, which increases with mass in agreement with predictions of the Λ cold dark matter paradigm. Assuming ΩM = 0.3, we found σ8 = 0.79 ± 0.16. We used the same clusters for measuring both lensing and clustering and the estimate of σ8 did require neither the mass-richness relation, nor the knowledge of the selection function, nor the modelling of b. With an additional theoretical prior on the bias, we obtained σ8 = 0.75 ± 0.08.
Volume
449
Issue
4
Start page
4147
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.449.4147S
Rights
open.access
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