Statistical anisotropy in CMB spectral distortions
  Measurements of the cosmic microwave background (CMB) spectral $y$-distortion
anisotropy offer a test for the statistical isotropy of the primordial density
perturbations on $0.01\lesssim k{\rm Mpc}\lesssim 1$. 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 $4\pi\langle y_{2m}\rangle=-6.8A_2\times
10^{-9}Y_{2m}(\mathbf d )$ with the quadruple Legendre coefficient of the
anisotropic powerspectrum $A_2$ and the $\ell=2$ spherical harmonics
$Y_{2m}(\mathbf d )$ for the preferred direction $\mathbf d $. Also, we discuss
the cosmic variance of the $y$-distortion anisotropy in the statistically
anisotropic Universe.
