Open AccessMultipole invariants and non‐Gaussianity
Author(s) -
Land Kate,
Magueijo João
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2005.00065.x
Subject(s) - bispectrum , multipole expansion , physics , cmb cold spot , non gaussianity , spectral density , cosmic microwave background , formalism (music) , statistical physics , gaussian , correlation function (quantum field theory) , astrophysics , theoretical physics , quantum mechanics , statistics , anisotropy , art , musical , mathematics , visual arts , dielectric
We propose a framework for separating the information contained in the cosmic microwave background multipoles, a ℓ m , into algebraically independent components that cleanly separate information pertaining to the power spectrum, non‐Gaussianity and preferred axis effects. The formalism builds upon the recently proposed multipole vectors and we elucidate a few features regarding these vectors, namely their lack of statistical independence for a Gaussian random process. In a few cases we explicitly relate our proposed invariants to components of the n ‐point correlation function (power spectrum, bispectrum). We find the distributions of the invariants using a mixture of analytical and numerical methods. We also evaluate them for the co‐added WMAP first‐year map.