First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Tests of Gaussianity

By E. Komatsu, Alan Kogut, M. Nolta, C. Bennett, Mark Halpern, Gary F. Hinshaw, N. Jarosik, M. Limon, S. Meyer, L. Page and 10 more. 2003

558 citations recorded by the source corpus.

We present limits to the amplitude of non-Gaussian primordial fluctuations in the WMAP 1 yr cosmic microwave background sky maps. A nonlinear coupling parameter, fNL, characterizes the amplitude of a quadratic term in the primordial potential. We use two statistics: one is a cubic statistic which measures phase correlations of temperature fluctuations after combining all configurations of the angular bispectrum. The other uses the Minkowski functionals to measure the morphology of the sky maps. Both methods find the WMAP data consistent with Gaussian primordial fluctuations and establish limits, -58 < fNL < 134, at 95% confidence. There is no significant frequency or scale dependence of fNL. The WMAP limit is 30 times better than COBE and validates that the power spectrum can fully characterize statistical properties of CMB anisotropy in the WMAP data to a high degree of accuracy. Our results also validate the use of a Gaussian theory for predicting the abundance of clusters in the local universe. We detect a point-source contribution to the bispectrum at 41 GHz, bsrc = (9.5 ± 4.4) × 10-5 μK3 sr2, which gives a power spectrum from point sources of csrc = (15 ± 6) × 10-3 μK2 sr in thermodynamic temperature units. This value agrees well with independent estimates of source number counts and the power spectrum at 41 GHz, indicating that bsrc directly measures residual source contributions.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/9d867d23f372a5dfc28e5dc000325122e9764cd9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Limits on non-Gaussianities from WMAP data (2005, methodology): “The collaboration analyzed their data searching for non-Gaussianity of the local form (2), finding the data to be consistent with purely Gaussian statistics and placing limits on the parameter f local NL [11]: −58 < f local NL < 134 at 95% C.”
Cosmological parameters from lensing power spectrum and bispectrum tomography (2003, background): “…1)/2 andns(ns + 1)(ns + 2)/6 for isosceles triangles, e.g.l1 = l2 6= l3, and equilateral triangles with l1 = l2 = l3, respectively. c© 0000 RAS, MNRAS000, 1–19 fNL < 100 from the CMB bispectrum measurement (Komatsu et al. 2003), the second term in equation (19) is much smaller than the first term.”
First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission (2003, unknown): “This value is also suggested by measurements of the bispectrum (Komatsu et al. 2003).”
Algorithms for bispectra: Forecasting, optimal analysis, and simulation (2006, methodology): “This greatly extends the generality of existing methods for simulating non-Gaussian fields (Komatsu et al. 2003; Liguori, Matarrese & Moscardini 2003; Contaldi & Magueijo 2001; Rocha et al. 2005).”
Ghost Inflation (2003, background): “The present limit on the non-gaussianity parameter from the WMAP collaboration [13]”
Non-Gaussian signatures in the temperature fluctuation observed by the Wilkinson Microwave Anisotropy Probe (2003, methodology): “Recently, Komatsu et al. (2003) have presented limits to the amplitude of non-Gaussian primordial fluctuations in the WMAP 1-yr CMB maps by measuring the C© 2004 RAS Downloaded from https://academic.oup.com/mnras/article-abstract/349/1/313/3101608 by guest on 26 July 2018 bispectrum and Minkowski…”
The shape of non-Gaussianities (2004, background): “The most stringent limit comes from the WMAP experiment [16] −58 < fNL < 134 at 95% C.”
Cosmological Perturbations From Inhomogeneous Reheating, Freeze-Out, and Mass Domination (2003, background): “tthesuper-horizon gravitationalpotential ﬂuctuations (during the matter-dominated era) are of the form Φ = g+fnl g2, (22) where gis Gaussian, the WMAP results are −58 <fnl <134 at 95% conﬁdence [4]. The Sloan Digital Sky Survey should provide similar accuracy [5]. The standard one-ﬁeld slow-ro”
SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: POWER SPECTRA AND WMAP-DERIVED PARAMETERS (2010, methodology): “The statistical properties of the CMB fluctuations measured by WMAP are close to Gaussian with random phase (Komatsu et al. 2003; Spergel et al. 2007; Komatsu et al. 2009).”