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Description
We present a numerical proof of the concept that the void spin distributions can provide a tight constraint on $\sigma_{8}$ without without being severely deteriorated by the degeneracies of $\sigma_{8}$ with $\Omega_{\rm cdm}h^{2}$, $M_{\nu}$ and $w$. Applying the Void-Finder algorithm to AbacusSummit N-body simulations of 15 different cosmological models, we identify the voids and measure the magnitudes of rescaled specific angular momenta of void halos as their spins. We determine the probability density distribution of void spins for each model and for the first time find it to be well approximated by the generalized Gamma distribution. It turns out that the best-fit values exhibit very sensitive dependence only on $\sigma_{8}$. This exclusive $\sigma_{8}$-dependence of the void spin distributions is confirmed to be robust against the variation of the mass and number cuts of void halos. We also test an observational feasibility of estimating the void spins from real data on the galaxy redshifts.
| References | Kang, G. and Lee, J., “Void spin distribution as a powerful probe of σ_8”, Journal of Cosmology and Astroparticle Physics, vol. 2025, no. 6, Art. no. 011, IOP, 2025. doi:10.1088/1475-7516/2025/06/011. |
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