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تسجيل مستخدم جديدCross-correlation of 2MASS and WMAP3: Implications for the Integrated Sachs-Wolfe effect
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We perform a cross-correlation of the Cosmic Microwave Background (CMB) using the third year Wilkinson Microwave Anisotropy Probe (WMAP) data with the 2 Micron All Sky Survey (2MASS) galaxy map (about 828 000 galaxies with median redshift z ~ 0.07). One motivation is to detect the Integrated Sachs-Wolfe (ISW) effect, expected if the cosmic gravitational potential is time dependent; for example, as it is in a flat universe with a Dark Energy component. The measured spherical harmonic cross-correlation signal favours the ISW signal expected in the concordance LambdaCDM model over that of zero correlation, although both are consistent with the data within 2sigma. Within a flat LambdaCDM model we find a best fit value of Omega_Lambda=0.85 and Omega_Lambda < 0.89 (95% CL). The above limits assume a galaxy bias b_g(sigma_8/0.75) ~ 1.40 +/- 0.03, which we derived directly from the 2MASS auto-correlation. Another goal is to test if previously reported anomalies in the WMAP data are related to the galaxy distribution (the so-called ``Axis of Evil - AoE). No such anomaly is observed in the 2MASS data nor are there any observed AoE correlations between the 2MASS and WMAP3 data.
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