Publication Date:
2015-04-12
Description:
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 8 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 cold dark matter paradigm. Assuming M = 0.3, we found 8 = 0.79 ± 0.16. We used the same clusters for measuring both lensing and clustering and the estimate of 8 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 8 = 0.75 ± 0.08.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
Permalink