The WMAP Cold Spot

Cruz, M.; Martínez-González, E.; Vielva, P.

doi:10.1007/978-3-642-11250-8_37

Cited by 13 publications

(12 citation statements)

References 33 publications

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“…While the lingering worries about a posteriori nature of this particular anomaly make its significance difficult to quantify, the basic existence of the cold spot seems to be confirmed by most analyses. For comprehensive overviews of the cold spot, see [79,80].…”

Section: Special Regions: the Cold Spotmentioning

confidence: 99%

CMB anomalies after Planck

Schwarz

Copi

Huterer

et al. 2016

Class. Quantum Grav.

341

357

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Abstract. Several unexpected features have been observed in the microwave sky at large angular scales, both by WMAP an by Planck. Among those features is a lack of both variance and correlation on the largest angular scales, alignment of the lowest multipole moments with one another and with the motion and geometry of the Solar System, a hemispherical power asymmetry or dipolar power modulation, a preference for odd parity modes and an unexpectedly large cold spot in the Southern hemisphere. The individual p-values of the significance of these features are in the per mille to per cent level, when compared to the expectations of the best-fit inflationary ΛCDM model. Some pairs of those features are demonstrably uncorrelated, increasing their combined statistical significance and indicating a significant detection of CMB features at angular scales larger than a few degrees on top of the standard model. Despite numerous detailed investigations, we still lack a clear understanding of these large-scale features, which seem to imply a violation of statistical isotropy and scale invariance of inflationary perturbations. In this contribution we present a critical analysis of our current understanding and discuss several ideas of how to make further progress.

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Section: Special Regions: the Cold Spotmentioning

confidence: 99%

CMB anomalies after Planck

Schwarz

Copi

Huterer

et al. 2016

Class. Quantum Grav.

341

357

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“…Jaffe et al [14,15], Cayon et al [16] and McEwen et al [17,18] have investigated the Bianchi VII h anisotropic cosmological model as a possible explanation of the CS and other features of the WMAP low multipoles. Recently, Cruz et al [5,19] have pointed out that the CS could be produced by a cosmic texture, assuming that the CMB signal is a combination of the Gaussian and non-Gaussian parts. The present status of the problem of existence of the CS remains uncertain, despite the presence of a vast collection of theoretical suggestions.…”

mentioning

confidence: 99%

Understanding the WMAP Cold Spot mystery

Naselsky¹,

Christensen²,

Coles

et al. 2010

Astrophys. Bull.

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The first and third year data releases from the WMAP provide evidence of an anomalous Cold Spot (CS) at galactic latitude b=-57deg and longitude l=209deg. We have examined the properties of the CS in some detail in order to assess its cosmological significance. We have performed a cluster analysis of the local extrema in the CMB signal to show that the CS is actually associated with a large group of extrema rather than just one. In the light of this we have re-examined the properties of the WMAP ILC and co-added "cleaned" WCM maps, which have previously been used for the analysis of the properties of the signal in the vicinity of the CS. These two maps have remarkably similar properties on equal latitude rings for |b|>30deg, as well as in the vicinity of the CS. We have also checked the idea that the CMB signal has a non-Gaussian tail, localized in the low multipole components of the signal. For each ring we apply a linear filter with characteristic scale R, dividing the CMB signal in two parts: the filtered part, with characteristic scale above that of the filter R, and the difference between the initial and filtered signal. Using the filter scale as a variable, we can maximize the skewness and kurtosis of the smoothed signal and minimize these statistics for the difference between initial and filtered signal. We have discovered that the shape of the CS is formed primarily by the components of the CMB signal represented by multipoles between 10<=L<=20, with a corresponding angular scale about 5-10 degs. This signal leads to modulation of the whole CMB sky, clearly seen at |b|>30deg in both the ILC and WCM maps, rather than a single localized feature. After subtraction of this modulation, the remaining part of the CMB signal appears to be consistent with statistical homogeneity and Gaussianity.Comment: 35 pages, 17 figure

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“…The resulting Kolmogorov's map shows enhanced randomness, i.e. higher value of K-parameter in certain regions including the Cold Spot [6], the non-Gaussian anomaly in the southern sky. Notably, the K-parameter of the Cold Spot satisfies the criterion expected for the voids, namely, increase of the randomness towards the walls of the void which act as hyperbolic (deviating) lenses for the CMB [7,8].…”

Section: Introductionmentioning

confidence: 99%

Probing the Statistic in the Cosmic Microwave Background

et al. 2009

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Kolmogorov's statistic is used for the analysis of properties of perturbations in the Cosmic Microwave Background signal. We obtain the maps of the Kolmogorov stochasticity parameter for W and V band temperature data of WMAP which are differently affected by the Galactic disk radiation and then we model datasets with various statistic of perturbations. The analysis shows that the Kolmogorov's parameter can be an efficient tool for the separation of Cosmic Microwave Background from the contaminating radiations due to their different statistical properties.

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The WMAP Cold Spot

Cited by 13 publications

References 33 publications

CMB anomalies after Planck

CMB anomalies after Planck

Understanding the WMAP Cold Spot mystery

Probing the Statistic in the Cosmic Microwave Background

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