Superimposed oscillations in the WMAP data?

Abstract

The possibility that the cosmic variance outliers present in the recently released Wilkinson Microwave Anisotropy Probe (WMAP) multipole moments are due to oscillations in the primordial power spectrum is investigated. Since the most important contribution to the WMAP likelihood originates from the outliers at a relatively small angular scale (around the first Doppler peak), special attention is paid to these in contrast with previous studies on the subject which have concentrated on the large scales outliers only (i.e., the quadrupole and octupole). As a physically motivated example, the case where the oscillations are of trans-Planckian origin is considered. It is shown that the presence of the oscillations causes an important drop in the WMAP χ2 of about 15. The F test reveals that such a drop has a probability less than 0.06% to occur by chance and can therefore be considered as statistically significant.