Detection of the ISW effect and corresponding dark energy constraints
  Using a directional spherical wavelet analysis we detect the integrated Sachs-Wolfe (ISW) effect, indicated by a positive correlation between the Wilkinson Microwave Anisotropy Probe (WMAP) and NRAO VLA Sky Survey (NVSS) data, at the 3.9 sigma level. In a flat universe the detection of the ISW effect provides direct and independent evidence for dark energy. Moreover, we use our detection to constrain the dark energy density Omega_Lambda. We obtain estimates for Omega_Lambda consistent with other analysis techniques and data sets and rule out a zero cosmological constant at greater than 99% significance. 
J. D. McEwen (1), P. Vielva (2), M. P. Hobson (1), E.   Martinez-Gonzalez (2), A. N. Lasenby (1) ((1) University of Cambridg...