Band-power reconstruction of the primordial fluctuation spectrum by the maximum likelihood reconstruction method

TL;DR

This paper reconstructs the primordial fluctuation spectrum from WMAP data using maximum likelihood, revealing a significant deviation from a simple power-law spectrum with a low probability of occurring in standard models.

Contribution

It introduces a maximum likelihood method for spectrum reconstruction and identifies a notable deviation from power-law behavior in the primordial spectrum.

Findings

Detected a 3.3σ peak deviation from power-law spectrum.

Estimated only 2% probability for such a feature in standard models.

Reconstructed spectrum using covariance matrix analysis.

Abstract

The primordial curvature fluctuation spectrum is reconstructed by the maximum likelihood reconstruction method using the five-year Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background temperature anisotropy. We apply the covariance matrix analysis and decompose the reconstructed spectrum into statistically independent band-powers. The prominent peak off a simple power-law spectrum found in our previous analysis turn out to be a $3.3\sigma$ deviation. From the statistics of primordial spectra reconstructed from mock observations, the probability that a primordial spectrum including such excess is realized in a power-law model is estimated to be about 2%.