New Anomalies in Cosmic Microwave Background Anisotropy: Violation of the Isotropic Gaussian Hypothesis in Low-$l$ Modes
| dc.creator | Su, Shi-Chun | |
| dc.creator | Chu, M. -C. | |
| dc.date | 2008-05-09 | |
| dc.date | 2008-05-16 | |
| dc.date.accessioned | 2026-07-07T09:38:59Z | |
| dc.date.available | 2026-07-07T09:38:59Z | |
| dc.description | In the standard framework of cosmology, primordial density fluctuations are assumed to have an isotropic Gaussian distribution. We search for deviations from this assumption in the WMAP data for the low $l$ modes of Cosmic Microwave Background Anisotropies (CMBA), by studying the directions of the z-axis that maximize the $l=m$ modes and the resulting amplitudes of these modes. We find a general alignment of the directions for $l=2$ to 10 modes to within 1/4 of the northern hemisphere. This alignment can be regarded as a generalization of the recently discovered alignment of the $l=2$ and 3 modes - the so-called `Axis of Evil'. Furthermore, we find abnormally high (low) powers in the $l=m=6$, 12 - 17 ($l=m=5$) modes; the probabilities for having the anomalous amplitudes of the $l=m=5$, 6, 17 modes are about 0.1%, 1% and 1% respectively according to the Gaussian conjecture. The alignment and anomalous amplitudes for these low $l$ modes are very robust against foreground contamination or different cleaning strategies, suggesting a cosmological origin and possibly supporting a non-standard inflation. | |
| dc.identifier | https://arxiv.org/abs/0805.1316 | |
| dc.identifier | http://arxiv.org/abs/0805.1316 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/161009 | |
| dc.subject | Astrophysics | |
| dc.title | New Anomalies in Cosmic Microwave Background Anisotropy: Violation of the Isotropic Gaussian Hypothesis in Low-$l$ Modes | |
| dc.type | text |