PUB - Publikationen an der Universität Bielefeld

We revisit the alignments of the largest structures observed in the cosmicmicrowave background (CMB) using the seven and nine-year WMAP and first-yearPlanck data releases. The observed alignments -- the quadrupole with theoctopole and their joint alignment with the direction of our motion withrespect to the CMB (the dipole direction) and the geometry of the Solar System(defined by the Ecliptic plane) -- are generally in good agreement with resultsfrom the previous WMAP data releases. However, a closer look at full-sky dataon the largest scales reveals discrepancies between the earlier WMAP datareleases (three to seven-year) and the final nine-year release. There are alsodiscrepancies between all the WMAP data releases and the first-year Planckrelease. Nevertheless, both the WMAP and Planck data confirm the alignments ofthe largest observable CMB modes in the Universe. In particular, the p-valuesfor the mutual alignment between the quadrupole and octopole, and the alignmentof the plane defined by the two with the dipole direction, are both at thegreater than 3-sigma level for all three Planck maps studied. We also calculateconditional statistics on the various alignments and find that it is currentlydifficult to unambiguously identify a leading anomaly that causes the others oreven to distinguish correlation from causation.