Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices

Details Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices

2009-05-18

arxiv.org/abs/0905.2854v3

Mon.Not.Roy.Astron.Soc.399:1921-1933,2009

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

14 pages, 10 figures; minor revisions; accepted for publication by MNRAS

Scientific paper

10.1111/j.1365-2966.2009.15421.x

We continue the analysis of non-Gaussianities in the CMB by means of the scaling index method (SIM, Raeth, Schuecker & Banday 2007) by applying this method on the 5-year WMAP data. We compare each of the results with 1000 Monte Carlo simulations mimicing the Gaussian properties of the best fit $\Lambda CDM$-model. Based on the scaling indices, scale-dependent empirical probability distributions, moments of these distributions and $\chi^2$-combinations of them are calculated, obtaining similar results as in the former analysis of the 3-year data: We derive evidence for non-Gaussianity with a probability of up to 97.3% for the mean when regarding the KQ75-masked full sky and summing up over all considered length scales by means of a diagonal $\chi^2$-statistics. Looking at only the northern or southern hemisphere, we obtain up to 98.5% or 96.6%, respectively. For the standard deviation, these results appear as 95.6% for the full sky (99.7% north, 89.4% south) and for a $\chi^2$-combination of both measurements as 97.4% (99.1% north, 95.5% south). By performing an analysis of rotated hemispheres, we detect an obvious asymmetry in the data. In addition to these investigations, we present a method of filling the mask with Gaussian noise to eliminate boundary effects caused by the mask. With the help of this technique, we identify several local features on the map, of which the most significant one turns out to be the well-known cold spot. When excluding all these spots from the analysis, the deviation from Gaussianity increases, which shows that the discovered local anomalies are not the reason of the global detection of non-Gaussianity, but actually were damping the deviations on average. Our analyses per band and per year suggest, however, that it is very unlikely that the detected anomalies are due to foreground effects.

Affiliated with

Also associated with

No associations

Rating

Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-609410