Reconstructing the primordial power spectrum

We reconstruct the shape of the primordial power spectrum from the latest cosmic microwave background data, including the new results from the Wilkinson microwave anisotropy probe (WMAP), and large-scale structure data from the two degree field galaxy redshift survey (2dFGRS). We take into account the uncertainties in four cosmological parameters. We use a model independent parameterization, with 16 bands in wavenumber, and find no obvious sign of deviation from a power law spectrum on the scales investigated. Furthermore, the values of the other cosmological parameters defining the model remain relatively well constrained despite the freedom in the shape of the initial power spectrum. (C) 2003 Published by Elsevier B.V.