2006/09/06 by P. Vielva, Patricio Vielva, Yves Wiaux +5 · 1 citation
Computer Science · Physics and Astronomy · #CMB cold spot #Computation #Computational Physics and Python Applications #Cosmic microwave background #Cosmology and Gravitation Theories #Dipole #Ecliptic #Filter (signal processing) #Particle physics theoretical and experimental studies #Position (finance) #Wavelet #astro-ph
paper · pdf · doi:10.1016/j.newar.2006.09.007
published as New Astron.Rev. 50 (2006) 880-888 · 14 pages, 8 figures. Proceedings of the Fundamental Physics With CMB workshop, UC Irvine, March 23-25, 2006, to be published in New Astronomy Reviews
arxiv created 2006/09/06 · openalex publication_date 2006/10/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
This paper reviews the application of a novel methodology for analysing the isotropy of the universe by probing the alignment of local structures in the CMB. The strength of the proposed methodology relies on the steerable wavelet filtering of the CMB signal. One the one hand, the filter steerability renders the computation of the local orientation of the CMB features affordable in terms of computation time. On the other hand, the scale-space nature of the wavelet filtering allows to explore the alignment of the local structures at different scales, probing possible different phenomena. We present the WMAP first-year data analysis recently performed by the same authors (Wiaux et al.), where an extremely significant anisotropy was found. In particular, a preferred plane was detected, having a normal direction with a northern end position close to the northern end of the CMB dipole axis. In addition, a most preferred direction was found in that plane, with a northern end direction very close to the north ecliptic pole. This result synthesised for the first time previously reported anomalies identified in the direction of the dipole and the ecliptic poles axes. In a forthcoming paper (Vielva et al.), we have extended our analysis to the study of individual frequency maps finding first indications for discarding foregrounds as the origin of the anomaly. We have also tested that the preferred orientations are defined by structures homogeneously distributed in the sky, rather than from localised regions. We have also analysed the WMAP 3-year data, finding the same anomaly pattern, although at a slightly lower significance level.