Previrialization: Perturbative and N-Body Results

Abstract

view Abstract Citations (59) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Previrialization: Perturbative and N-Body Results Lokas, E. L. ; Juszkiewicz, R. ; Bouchet, F. R. ; Hivon, E. Abstract We present a series of N-body experiments which confirm the reality of the previrialization effect. We use also a weakly nonlinear perturbative approach to study the phenomenon. These two approaches agree when the rms density contrast, σ, is small; more surprisingly, they remain in agreement when σ ~ 1. When the slope of the initial power spectrum is n > -1, nonlinear tidal interactions slow down the growth of density fluctuations, and the magnitude of the suppression increases when n (i.e., the relative amount of small-scale power) is increased. For n < -1, we see an opposite effect: the fluctuations grow more rapidly than in linear theory. The transition occurs at n = -1 when the weakly nonlinear correction to σ is close to zero and the growth rate is close to linear. Our results resolve recent controversy between two N- body studies of previrialization. Peebles assumed n = 0 and found strong evidence in support of previrialization, while Evrard & Crone, who assumed n = -1, reached opposite conclusions. As we show here, the initial conditions with n = -1 are rather special because the nonlinear effects nearly cancel out for that particular spectrum. In addition to our calculations for scale-free initial spectra, we show results for a more realistic spectrum of Peacock & Dodds. Its slope near the scale usually adopted for normalization is close to -1, so σ is close to linear. Our results retroactively justify linear normalization at 8 h^-1^ Mpc while also demonstrating the danger and limitations of this practice. Publication: The Astrophysical Journal Pub Date: August 1996 DOI: 10.1086/177580 arXiv: arXiv:astro-ph/9508032 Bibcode: 1996ApJ...467....1L Keywords: COSMOLOGY: THEORY; GALAXIES: FORMATION; COSMOLOGY: LARGE-SCALE STRUCTURE OF UNIVERSE; Astrophysics E-Print: Significantly revised, 25 pages, uuencoded compressed postscript, figures included, to appear in ApJ full text sources arXiv | ADS |