Large-angle anomalies in the CMB

TL;DR

This paper reviews large-scale anomalies in the cosmic microwave background, including alignments and low power at large scales, discussing their significance and potential explanations within cosmology.

Contribution

It provides a comprehensive review of recent large-angle anomalies in the CMB and evaluates their implications for standard inflationary models.

Findings

Detection of alignments in large-scale CMB modes

Observation of unusually low power at large scales

Discussion of potential explanations for anomalies

Abstract

We review the recently found large-scale anomalies in the maps of temperature anisotropies in the cosmic microwave background. These include alignments of the largest modes of CMB anisotropy with each other and with geometry and direction of motion of the Solar System, and the unusually low power at these largest scales. We discuss these findings in relation to expectation from standard inflationary cosmology, their statistical significance, the tools to study them, and the various attempts to explain them.