Absence of significant cross-correlation between WMAP and SDSS (Articolo in rivista)

Type
Label
  • Absence of significant cross-correlation between WMAP and SDSS (Articolo in rivista) (literal)
Anno
  • 2010-01-01T00:00:00+01:00 (literal)
Alternative label
  • Lopez-Corredoira M.; Sylos Labini F.; Betancort-Rijo J. (2010)
    Absence of significant cross-correlation between WMAP and SDSS
    in Astronomy & astrophysics (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Lopez-Corredoira M.; Sylos Labini F.; Betancort-Rijo J. (literal)
Pagina inizio
  • A3 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 513 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#note
  • (April). European Southern Observatory (ESO), EDP Sciences. (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Instituto de Astrof´ýsica de Canarias, E-38200 La Laguna, Tenerife, Spain and Departamento de Astrof´ýsica, Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain, Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89 A, Compendio del Viminale, 00184 Rome and CNR-ISC, Rome (literal)
Titolo
  • Absence of significant cross-correlation between WMAP and SDSS (literal)
Abstract
  • Aims. Several authors have claimed to detect a significant cross-correlation between microwave WMAP anisotropies and the SDSS galaxy distribution. We repeat these analyses to determine the different cross-correlation uncertainties caused by re-sampling errors n and field-to-field fluctuations. The first type of error concerns overlapping sky regions, while the second type concerns non-overlapping sky regions. Methods. To measure the re-sampling errors, we use bootstrap and jack-knife techniques. For the field-to-field fluctuations, we use three methods: 1) evaluation of the dispersion in the cross-correlation when correlating separated regions of WMAP with the original region of SDSS; 2) use of mock Monte Carlo WMAP maps; 3) a new method (developed in this article), which measures the error as a function of the integral of the product of the self-correlations for each map. Results. The average cross-correlation for b 30 deg. is significantly stronger than the re-sampling errors¡ªboth the jack-knife and bootstrap techniques provide similar results¡ªbut it is of the order of the field-to-field fluctuations. This is confirmed by the cross-correlation between anisotropies and galaxies in more than the half of the sample being null within re-sampling errors. Conclusions. Re-sampling methods underestimate the errors. Field-to-field fluctuations dominate the detected signals. The ratio of signal to re-sampling errors is larger than unity in a way that strongly depends on the selected sky region. We therefore conclude that there is no evidence yet of a significant detection of the integrated Sachs-Wolfe (ISW) effect. Hence, the value of ? ¡Ö0.8 obtained by the authors who assumed they were observing the ISWeffect would appear to have originated from noise analysis. (literal)
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