Cosmic shear measurements have now improved to the point where they deserve to be treated on par with CMB and galaxy clustering data for cosmological parameter analysis , using the full measured aperture mass variance curve rather than a mere phenomenological parametrization thereof .
We perform a detailed 9-parameter analysis of recent lensing ( RCS ) , CMB ( up to Archeops ) and galaxy clustering ( 2dF ) data , both separately and jointly .
CMB and 2dF data are consistent with a simple flat adiabatic scale-invariant model with \Omega _ { \Lambda } = 0.72 \pm 0.09 , h ^ { 2 } \Omega _ { cdm } = 0.115 \pm 0.013 , h ^ { 2 } \Omega _ { b } = 0.024 \pm 0.003 , and a hint of reionization around z \sim 8 .
Lensing helps further tighten these constraints , but reveals tension regarding the power spectrum normalization : including the RCS survey results raises \sigma _ { 8 } significantly and forces other parameters to uncomfortable values .
Indeed , \sigma _ { 8 } is emerging as the currently most controversial cosmological parameter , and we discuss possible resolutions of this \sigma _ { 8 } problem .
We also comment on the disturbing fact that many recent analyses ( including this one ) obtain error bars smaller than the Fisher matrix bound .
We produce a CMB power spectrum combining all existing experiments , and using it for a “ MAP versus world ” comparison next month will provide a powerful test of how realistic the error estimates have been in the cosmology community .