Statistical anisotropy in CMB spectral distortions

Atsuhisa Ota
2019 Physics Letters B  
Measurements of the cosmic microwave background (CMB) spectral y-distortion anisotropy offer a test for the statistical isotropy of the primordial density perturbations on 0.01≲ k Mpc≲ 1. We compute the 1-point ensemble averages of the y-distortion anisotropies which vanish for the statistically isotropic perturbations. For the quadrupole statistical anisotropy, we find 4π〈 y_2m〉=-6.8A_2× 10^-9Y_2m( d ) with the quadruple Legendre coefficient of the anisotropic powerspectrum A_2 and the ℓ=2
more » ... A_2 and the ℓ=2 spherical harmonics Y_2m( d ) for the preferred direction d . Also, we discuss the cosmic variance of the y-distortion anisotropy in the statistically anisotropic Universe.
doi:10.1016/j.physletb.2019.01.030 fatcat:qn7xwppq5veltfvnaoffc7gy3y