Probing dark energy with steerable wavelets through correlation of WMAP and NVSS local morphological measures

Jason D McEwen, Yves Wiaux, M. P. Hobson, Pierre Vandergheynst, A. N. Lasenby

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


Using local morphological measures on the sphere defined through a steerable wavelet analysis, we examine the three-year Wilkinson Microwave Anisotropy Probe WMAP and the NRAO VLA Sky Survey (NVSS) data for correlation induced by the integrated Sachs-Wolfe (ISW) effect. The steerable wavelet constructed from the second derivative of a Gaussian allows one to define three local morphological measures, namely the signed-intensity, orientation and elongation of local features. Detections of correlation between the WMAP and NVSS data are made with each of these morphological measures. The most significant detection is obtained in the correlation of the signed-intensity of local features at a significance of 99.9 per cent. By inspecting signed-intensity sky maps, it is possible for the first time to see the correlation between the WMAP and NVSS data by eye. Foreground contamination and instrumental systematics in the WMAP data are ruled out as the source of all significant detections of correlation. Our results provide new insight on the ISW effect by probing the morphological nature of the correlation induced between the cosmic microwave background and large-scale structure of the Universe. Given the current constraints on the flatness of the Universe, our detection of the ISW effect again provides direct and independent evidence for dark energy. Moreover, this new morphological analysis may be used in future to help us to better understand the nature of dark energy.

Original languageEnglish
Pages (from-to)1289-1300
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 11 Mar 2008


  • Cosmic microwave background
  • Cosmology: observations
  • Methods: data analysis
  • Methods: numerical

ASJC Scopus subject areas

  • Space and Planetary Science


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