Cross-correlation of 2MASS and WMAP 3: implications for the integrated Sachs–Wolfe effect

We perform a cross-correlation of the cosmic microwave background using the third year Wilkinson Microwave Anisotropy Probe (WMAP) data with the Two 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 Lambda cold dark matter (� CDM) model over that of zero correlation, although