1207.1183 (Chiaki Hikage et al.)

Limits on Second-Order Non-Gaussianity from Minkowski Functionals of WMAP Data    [PDF]

Chiaki Hikage, Takahiko Matsubara

We analyze non-Gaussianity (NG) due to primordial bispectrum and trispectrum using CMB temperature maps of WMAP 7-year data. We first apply the perturbative formulae of Minkowski functionals upto second-order NG derived by Matsubara (2010), which enable us to give limits on the cubic NG parameterized with tau_NL and g_NL as well as various types of quadratic NG parameterized with f_NL. We find no signature of primordial NG in WMAP data, but give constraints on the local-type, equilateral-type, orthogonal-type f_NL: f_NL(loc)=20+-42, f_NL(eq)=-121+-208, f_NL(ort)=-129+-171, and tau_NL/10^4=-7.6+-8.7, and g_NL/10^5=-1.9+-6.4. We also find that these constraints are consistent with the limits from skewness and kurtosis parameters which characterize the perturbative corrections of MFs.

View original: http://arxiv.org/abs/1207.1183