Precise measurements of the anisotropies in the cosmic microwave background enable us to do an accurate study on the form of the primordial power spectrum for a given set of cosmological parameters .
In a previous paper ( ( 1 ) ) , we implemented an improved ( error sensitive ) Richardson-Lucy deconvolution algorithm on the measured angular power spectrum from the first year of WMAP data to determine the primordial power spectrum assuming a concordance cosmological model .
This recovered spectrum has a likelihood far better than a scale invariant , or , ‘ best fit ’ scale free spectra ( \Delta \ln { \cal L } \approx 25 w.r.t . Harrison Zeldovich , and , \Delta \ln { \cal L } \approx 11 w.r.t . power law with n _ { s } = 0.95 ) .
In this paper we use Discrete Wavelet Transform ( DWT ) to decompose the local features of the recovered spectrum individually to study their effect and significance on the recovered angular power spectrum and hence the likelihood .
We show that besides the infra-red cut off at the horizon scale , the associated features of the primordial power spectrum around the horizon have a significant effect on improving the likelihood .
The strong features are localized at the horizon scale .