On the Robustness of the Acoustic Scale in the Low-Redshift Clustering of Matter


Eisenstein DJ, Seo H-J, White M. On the Robustness of the Acoustic Scale in the Low-Redshift Clustering of Matter. The Astrophysical Journal. 2007;664 :660-674.

Date Published:

August 1, 2007


We discuss the effects of nonlinear structure formation on the signatureof acoustic oscillations in the late-time galaxy distribution. We arguethat the dominant nonlinear effect is the differential motion of pairsof tracers separated by 150 Mpc. These motions are driven by bulk flowsand cluster formation and are much smaller than the acoustic scaleitself. We present a model for the nonlinear evolution based on thedistribution of pairwise Lagrangian displacements that provides aquantitative model for the degradation of the acoustic signature, evenfor biased tracers in redshift space. The Lagrangian displacementdistribution can be calibrated with a significantly smaller set ofsimulations than would be needed to construct a precise power spectrum.By connecting the acoustic signature in the Fourier basis with that inthe configuration basis, we show that the acoustic signature is morerobust than the usual Fourier-space intuition would suggest, because thebeat frequency between the peaks and troughs of the acousticoscillations is a very small wavenumber that is well inside the linearregime. We argue that any possible shift of the acoustic scale is