Constraints on Neutrino Mass with Void Weak Lensing Effect

Abstract

Cosmic voids, the underdense regions of the Large Scale Structure (LSS), provide cosmological information highly complementary to that obtained from overdense regions. In this work, we investigate the constraining power of the void-shear cross-correlation (void lensing effect) on the total neutrino mass. Based on cosmological simulations with varying neutrino masses, we identify voids with the DIVE void finder and obtain their density profiles from the underlying dark matter and neutrino distributions. We then generate mock shear catalogues through ray-tracing and measure the corresponding void lensing signals. Our results show that void lensing yields an independent constraint on total neutrino mass as $σ(M_ν)=0.096\,{\rm eV}$ in the absence of shape noise, and $σ(M_ν)=0.340\,{\rm eV}$ when adopting a Stage-III-like shape noise ($σ_e \simeq 0.3$). Moreover, we find a clear linear relationship between the void lensing signal and neutrino mass. We further validate the forward modelling of the void lensing signal from the void density profiles across different cosmologies, demonstrating its accuracy and potential for future applications. These findings highlight void lensing as a promising probe of massive neutrinos and motivate its applications to galaxy survey data as well as the combination with other cosmological observables.

Figures (11)

• Figure 1: The results of HOD fitting. Lines in different colors indicate the best-fit projected 2-point correlation function in simulations with different neutrino masses. The black data points show the projected clustering of BOSS LRGs in $0.2<z<0.4$ and the errorbars are estimated with 1000 PATCHY mocks.
• Figure 2: Shear auto-correlation functions $\xi_{+}$ (red) and $\xi_{-}$ (blue). The data points are the measurements in our mock source catalogues using treecorrtreecorr and the errorbars are estimated in 15 realizations (see Section \ref{['subsec:covariance']}). Here we incorporate a shape noise $\sigma_e=0.3$ in the catalogues. The solid lines are the prediction of 3D matter power spectrum calculated with pycclpyccl.
• Figure 3: Combined density profiles of voids with $17<R_V<25$ Mpc/h measured in simulations. Different colors represent simulations with different neutrino masses. The left panel shows the total density profile, while the right panel presents dark matter and neutrino components separately with solid and dotted lines. The bottom panels display the differences between simulations with massive neutrinos and massless neutrinos ($\delta_0(r)$.
• Figure 4: Theoretical model of the combined void lensing signal $\Delta \Sigma$ for voids with $17<R<25$ Mpc/h. Different colors indicate different neutrino masses. The bottom panel shows the differences between results of massive neutrinos and the massless case.
• Figure 5: Comparison between void lensing signal measured in ray-tracing mocks (data points) and theoretical models (solid lines). The radius ranges of measurement are $0.3 \le R/R_V \le 1.8$ with a bin size $\Delta R=0.1R_V$. Different colors indicate the measurements in simulations with $M_{\nu}=0.0\,{\rm eV}$ (red) and $M_{\nu}=0.4\,{\rm eV}$ (green). The left panel shows the measurements from mock source catalogues without shape noise, while the right panels display the results including shape noise $\sigma_e=0.3$. The errorbars are estimated with 15 realizations in Section \ref{['subsec:covariance']}. Two bottom panels show the differences between the mock measurements ($\Delta \Sigma_{\rm rt}$) and models ($\Delta \Sigma_{\rm theo}$).