Probing massive neutrinos with the Minkowski functionals of large-scale structure

Abstract

Massive neutrinos suppress the growth of structure under their free-streaming scales. The effect is most prominent on small scales where the widely-used two-point statistics can no longer capture the full information. In this work, we study the signatures massive neutrinos leave on large-scale structure (LSS) as revealed by its morphological properties, which are fully described by $4$ Minkowski functionals (MFs), and quantify the constraints on the summed neutrino mass $M_{\nu}$ from the MFs, by using publicly available N-body simulations. We find the MFs provide important complementary information, and give tighter constraints on $M_{\nu}$ than the power spectrum. Specifically, depending on whether massive neutrinos are included in the density field (the `m' field) or not (the `cb' field), we find the constraint on $M_{\nu}$ from the MFs with a smoothing scale of $R_G=5 h^{-1}$Mpc is $48$ or $4$ times better than that from the power spectrum. When the MFs are combined with the power spectrum, they can improve the constraint on $M_{\nu}$ from the latter by a factor of 63 for the `m' field and 5 for the `cb' field. Notably, when the `m' field is used, the constraint on $M_{\nu}$ from the MFs can reach $0.0177$eV with a volume of $1(h^{-1}\rm Gpc)^3$, while the combination of the MFs and power spectrum can tighten this constraint to be $0.0133$eV, a $4.5\sigma$ significance on detecting the minimum sum of the neutrino masses. For the `m' field, we also find the $\sigma_8$ and $M_{\nu}$ degeneracy is broken with the MFs, leading to stronger constraints on all 6 cosmological parameters considered in this work than the power spectrum.