Cosmic shear statistics in the Suprime-Cam 2.1 sq deg field: Constraints on Omega_m and sigma_8
Abstract
We present measurements of cosmic shear correlations in the Suprime-Cam 2.1 deg^2 Rc-band imaging data. For an estimator of the gravitational lensing origin shear correlation, we adopt the aperture mass variance which most naturally decomposes the correlation signal into E and B modes. We detect the non-zero E mode variance on scales between 2 and 40 arcmin. We also detect the small but non-zero B mode variance on scales larger than 5 arcmin. We perform the maximum likelihood analysis in a four-dimensional space of sigma_8, Omega_m, Gamma, and a mean redshift of galaxies zs. We include three possible sources of error: a statistical noise, cosmic variance, and a residual systematic. We derive joint constraints on two parameters by marginalizing over two remaining parameters. We obtain an upper limit of Gamma0.7 (90% confidence). For a prior Gamma\in[0.1,0.4] and zs\in[0.8,1.4], we find sigma_8=(0.41_{-0.16}^{+0.21})Omega_m^{-0.43} for flat cosmologies and sigma_8=(0.43_{-0.18}^{+0.20})Omega_m^{-0.24}$ for open cosmologies (95% confidence). If we take the currently popular LCDM model, we obtain a one-dimensional confidence interval on sigma_8 for the 95.4% level, 0.47<sigma_8<1.10 for zs\in[0.6,1.4]. It is demonstrated that the information on the redshift distribution of galaxies is the key to obtaining a correct cosmological constraint, and that an independent constraint on Gamma from other observations is useful to tighten the constraint.Keywords
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