Astronomy & Astrophysics Bianchi type VIIh models and the WMAP 3 - year data ( Research
نویسندگان
چکیده
Context. A specific example of Bianchi type VIIh models, i.e. those including universal rotation (vorticity) and differential expansion (shear), has been shown in Jaffe et al. (2005, ApJ, 629, L1) to correlate unexpectedly with the WMAP first-year data. Aims. We re-assess the signature of this model in the WMAP 3-year data. Methods. The cross-correlation methods are described in Jaffe et al. (2006a, ApJ, 643, 616). We use the WMAP 3-year data release, including maps for individual years, and perform additional comparisons to assess the influence of both noise and residual foregrounds and eliminate potential non-cosmological sources for the correlation. Results. We confirm that the signal is detected in both the combined 3-year data and the individual yearly sky maps at a level consistent with our original analysis. The significance of the correlation is not affected by either noise or foreground residuals. Conclusions. The results of our previous study are unchanged.
منابع مشابه
Unveiling Hidden Patterns in CMB Anisotropy Maps
Bianchi VIIh models have been recently proposed to explain potential anomalies in the CMB anisotropy as observed by WMAP. We investigate the statistical isotropy of embedded Bianchi VIIh templates in the CMB anisotropy maps to determine whether the existence of a hidden Bianchi template in the WMAP data is consistent with the previous null detection of the bipolar power spectrum in the WMAP fir...
متن کاملBianchi Type VII h Models and the WMAP 3 - year Data ( Research Note
Context. A specific example of Bianchi Type VIIh models, i.e. those including universal rotation (vorticity) and differential expansion (shear), has been shown in Jaffe et al. (2005) to correlate unexpectedly with the WMAP first-year data. Aims. We re-assess the signature of this model in the WMAP 3-year data. Methods. The cross-correlation methods are described in Jaffe et al. (2006a). We use ...
متن کاملNon-Gaussianity detections in the Bianchi VIIh corrected WMAP 1-year data made with directional spherical wavelets
Many of the current anomalies reported in the Wilkinson Microwave Anisotropy Probe (WMAP) 1-year data disappear after ‘correcting’ for the best-fit embedded Bianchi type VIIh component (Jaffe et al. 2005), albeit assuming no dark energy component. We investigate the effect of this Bianchi correction on the detections of non-Gaussianity in the WMAP data that we previously made using directional ...
متن کاملMarkov chain Monte Carlo analysis of Bianchi VIIh models
We have extended the analysis of Jaffe et al. (2005a, 2006) to a complete Markov chain Monte Carlo (MCMC) parameter space study of the Bianchi type VIIh models including a dark energy density, using Wilkinson Microwave Anisotropy Probe (WMAP) cosmic microwave background (CMB) data from the 1-year and 3-year releases. Since we perform the analysis in a Bayesian framework our entire inference is ...
متن کاملEvidence of Vorticity and Shear at Large Angular Scales in the Wmap Data: a Violation of Cosmological Isotropy?
Motivated by the large-scale asymmetry observed in the cosmic microwave background sky, we consider a specific class of anisotropic cosmological models – Bianchi type VIIh – and compare them to the WMAP first-year data on large angular scales. Remarkably, we find evidence of a correlation which is ruled out as a chance alignment at the 3σ level. The best fit Bianchi model corresponds to x = 0.5...
متن کامل