Nonlinear Evolution of Anisotropic Cosmological Power
There has been growing interest in the possibility of testing more precisely the assumption of statistical isotropy of primordial density perturbations. If it is to be tested with galaxy surveys at distance scales <~10 Mpc, then nonlinear evolution of anisotropic power must be understood. To this end, we calculate the angular dependence of the power spectrum to third order in perturbation theory for a primordial power spectrum with a quadrupole dependence on the wave vector direction. Our results suggest that primordial power anisotropies will be suppressed by <~7% in the quasilinear regime. We also show that the skewness in the statistically anisotropic theory differs by no more than 1% from that in the isotropic theory.
Additional Information© 2008 The American Physical Society. (Received 5 November 2007; published 21 February 2008) M.K. acknowledges the hospitality of the Aspen Center for Physics, where part of this work was completed. This work was supported by the Sherman Fairchild Foundation (S.A.), DoE No. DE-FG03-92-ER40701, NASA No. NNG05GF69G, and the Gordon and Betty Moore Foundation (M.K.).
Published - ANDprl08.pdf