Probing Large-Angle Correlations with the Microwave Background Temperature and Lensing Cross Correlation

Abstract

A lack of correlations in the microwave background temperature between sky directions separated by angles larger than 60 degrees has recently been confirmed by data from the Planck satellite. This feature arises as a random occurrence within the standard LCDM cosmological model less than 0.3 per cent of the time, but so far no other compelling theory to explain this observation has been proposed. Here we investigate the theoretical cross-correlation function between microwave background temperature and the gravitational lensing potential of the microwave background, which in contrast to the temperature correlation function depends strongly on gravitational potential fluctuations interior to our Hubble volume. For standard LCDM cosmology, we generate random sky realizations of the microwave temperature and gravitational lensing, subject to the constraint that the temperature correlation function matches observations, and compare with random skies lacking this constraint. The distribution of large-angle temperature-lensing correlation functions in these two cases is different, and the two cases can be clearly distinguished in around 40 per cent of model realizations. We present an a priori procedure for using similar large-angle correlations between other types of data, to determine whether the lack of large-angle correlations is a statistical fluke or points to a shortcoming of the standard cosmological model.

6 pages, 5 figures, submitted to MNRAS

References in corpus (5)

• Planck 2018 results. VII. Isotropy and Statistics of the CMB
• Hemispherical power asymmetry in the three-year Wilkinson Microwave Anisotropy Probe sky maps
• The Uncorrelated Universe: Statistical Anisotropy and the Vanishing Angular Correlation Function in WMAP Years 1-3
• Lack of large-angle TT correlations persists in WMAP and Planck
• The Hot and Cold Spots in Five-Year WMAP Data

Cited by in corpus (11)

• CMB Anomalies after Planck
• Covariance of CMB anomalies
• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• Towards testing CMB anomalies using the kinetic and polarized Sunyaev Zel'dovich effects
• A Bayesian analysis of inflationary primordial spectrum models using Planck data
• Tensor to scalar ratio and large scale power suppression from pre-slow roll initial conditions
• Microwave Background Polarization as a Probe of Large-Angle Correlations
• The ISW effect and the lack of large-angle CMB temperature correlations
• Testing CMB Anomalies in E-mode Polarization with Current and Future Data
• Exploring suppressed long-distance correlations as the cause of suppressed large-angle correlations
• New Geometric Representations of the CMB 2pcf