Bibliographic Information: Esposito, M., SΓ‘nchez, A. G., Bel, J., & Ruiz, A. N. (202X). Evolution mapping II: describing statistics of the non-linear cosmic velocity field. Monthly Notices of the Royal Astronomical Society, 000, 1β10. Preprint: arXiv:2406.08539v2 [astro-ph.CO]
Research Objective: This research paper aims to extend the application of evolution mapping, a technique previously used to describe non-linear matter density fluctuations, to the statistics of the cosmic velocity field. The authors investigate whether this approach can simplify the modeling of velocity statistics and accurately capture their behavior in different cosmological models.
Methodology: The authors utilize a suite of N-body simulations called the Aletheia simulations, which share the same shape parameters but differ in their evolution parameters. They analyze snapshots from these simulations at redshifts where the different cosmologies exhibit the same linear matter clustering amplitude. To estimate the volume-weighted velocity field from the simulations, the authors employ a modified Voronoi tessellation method. They then compute the velocity divergence auto-power spectrum (πππ(π)) and its cross-power spectrum with the density field (ππΏπ(π)).
Key Findings: The study demonstrates that the evolution mapping relation, which states that cosmologies with identical shape parameters but different evolution parameters exhibit similar non-linear evolutions when expressed as a function of clustering amplitude, holds true for both πππ(π) and ππΏπ(π). While deviations from perfect mapping occur in the strongly non-linear regime, the authors show that these deviations can be effectively modeled using the suppression factor π(π) = π·(π)/π, similar to the approach used for the density field.
Main Conclusions: The research concludes that evolution mapping provides a valuable framework for simplifying the description of the cosmological dependence of non-linear density and velocity statistics. By leveraging the relationship between clustering amplitude and non-linear evolution, this technique offers a more efficient way to sample large cosmological parameter spaces in cosmological analyses.
Significance: This research significantly contributes to the field of cosmology by providing a new tool for analyzing and interpreting the large-scale structure of the universe. The ability to accurately model velocity statistics using evolution mapping has important implications for understanding the dynamics of cosmic structures and for interpreting observational data from galaxy surveys.
Limitations and Future Research: The study primarily focuses on cosmologies without massive neutrinos. Future research could explore extending the evolution mapping framework to include the effects of massive neutrinos on the velocity field. Additionally, further investigation into different velocity field reconstruction techniques and their impact on the accuracy of evolution mapping could be beneficial.
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