Open AccessAnalysing large‐scale structure – II. Testing for primordial non‐Gaussianity in CMB maps using surrogates
Author(s) -
Räth Christoph,
Schuecker Peter
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06799.x
Subject(s) - cosmic microwave background , physics , non gaussianity , minkowski space , spectral density , scaling , amplitude , gaussian , noise (video) , statistical physics , cosmology , astrophysics , scale (ratio) , statistics , artificial intelligence , optics , quantum mechanics , computer science , mathematics , geometry , anisotropy , image (mathematics)
The identification of non‐Gaussian signatures in cosmic microwave background (CMB) temperature maps is one of the main cosmological challenges today. We propose and investigate alternative methods to analyse CMB maps. Using the technique of constrained randomization, we construct surrogate maps which mimic both the power spectrum and the amplitude distribution of simulated CMB maps containing non‐Gaussian signals. Analysing the maps with weighted scaling indices and Minkowski functionals yields in both cases statistically significant identification of the primordial non‐Gaussianities. We demonstrate that the method is very robust with respect to noise. We also show that Minkowski functionals are able to account for non‐linearities at higher noise level when applied in combination with surrogates than when only applied to noise added CMB maps and phase randomized versions of them, which only reproduce the power spectrum.