Skewness of the large-scale velocity divergence from non-Gaussian initial conditions

• Published in: Monthly notices of the Royal Astronomical Society Vol. 286; no. 1; pp. 223 - 228
• Main Authors: Protogeros, Zacharias A. M., Scherrer, Robert J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 21-03-1997
• Subjects: cosmology: theory; large-scale structure of Universe; large-scale structure of Universe; cosmology: theory
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/286.1.223

We compute the skewness t3 and the corresponding hierarchical amplitude T3 of the divergence of the velocity field for arbitrary non-Gaussian initial conditions. We find that T3 qualitatively resembles the corresponding hierarchical amplitude for the density field, S3, in that it contains a term proportional to the initial skewness, which decays inversely as the linear growth factor, plus a constant term which differs from the corresponding Gaussian term by a complex function of the initial three- and four-point functions. We extend the results for S3 and T3 with non-Gaussian initial conditions to evolved fields smoothed with a spherical top-hat window function. We show that certain linear combinations, namely S3 + 1/2T3, S3 + T3and s3 +t3, lead to expressions which are much simpler, for non-Gaussian initial conditions, than S3 and T3 (or s3 and t3) considered separately.