Inflationary Features and Shifts in Cosmological Parameters From Planck 2015 Data

Abstract

We explore the relationship between features in the Planck 2015 temperature and polarization data, shifts in the cosmological parameters, and features from inflation. Residuals in the temperature data from the best-fit power-law ΛCDM model at low multipole ℓ≲40 are mainly responsible for the high H0 and low σ8Ω1/2m values when comparing the ℓ<1000 portion to the full data set. These same residuals are better fit to inflationary features with a 1.9σ preference for running of the running of the tilt or a stronger 99% C.L. local significance preference for a sharp drop in power around k=0.004 Mpc−1, relieving the internal tension with H0. At ℓ>1000, the same in-phase acoustic residuals that drive the global H0 constraints and appear as a lensing anomaly also favor running parameters which allow even lower H0, but not once lensing reconstruction is considered. Polarization spectra are intrinsically highly sensitive to these parameter shifts, and even more so in the Planck 2015 TE data due to an anomalous suppression in power at ℓ≈165, which disfavors the best-fit H0 ΛCDM solution by more than 2σ, and high H0 value at almost 3σ. Current polarization data also slightly enhance the significance of a sharp suppression of large-scale power but leave room for large improvements in the future with cosmic variance limited E-mode measurements.