Anisotropic power spectrum and the observed low-l power in PLANCK CMB data

Abstract

In this work, we study a direction dependent power spectrum in anisotropic Finsler space-time. We use this direction dependent power spectrum to address the low-l power observed in WMAP and PLANCK data. The angular power spectrum of the temperature fluctuations has a lower amplitude in comparison to the ΛCDM model in the multipole range l = 2 - 40. Our theoretical model gives a correction to the isotropic angular power spectrum {C}_l^TT due to the breaking of rotational invariance of the primordial power spectrum. We estimate best-fit model parameters along with the six ΛCDM cosmological parameters using the PLANCK likelihood code in CosmoMC software. We find that this modified angular power spectrum fits the CMB temperature data in the multipole range l = 2 - 10 to a good extent but fails for the whole multipole range l = 2 - 40.