Weak lensing higher-order statistics to disentangle modified gravity and massive neutrinos

Abstract

Going beyond second order in weak lensing (WL) statistics is known to break degeneracies among cosmological parameters. We take a step further here, investigating whether higher-order statistics (HOS) in weak lensing can disentangle among General Relativity (GR) and modified gravity (MG), also taking into account the presence of massive neutrinos. To this end, we rely on mock convergence maps obtained from GR and $f(R)$ gravity N - body simulations, and we look for MG signatures in a wide set of higher-order WL probes. We rely on different metrics to quantify the discriminatory power of each probe, also varying the measurement setup. We find out that WL HOS can indeed disentangle MG and GR also in the presence of massive neutrinos.

Figures (6)

• Figure 1: Histograms of samples of a selected bin, at $z_s=2.0$, smoothing $2'.4$, for the 1 - PDF, obtained by counting the values of the statistic from the 256 maps of the DUSTGRAIN simulations falling into the given bin. The different distributions correspond respectively to $\Lambda$CDM, and the fR4 cosmologies with and without massive neutrinos. The solid lines come from the Gaussian smoothing obtained with KDE. The histograms are normalized so the total area equals unity.
• Figure 2: Values of $f_{mod}({\cal{O}}, {\cal{M}})$ as a function of the source redshift $z_s$ using the Hellinger distance as metric for fR4 cosmologies. Please note the scale change in the left panel for better viewing.
• Figure 3: Same as Fig. \ref{['fig: fmodvszshell1']} for fR5 and fR6 cosmologies. Please note the scale change in the last two fR6 plots for better viewing.
• Figure 4: CvM test results for the fR4 model setting $M_{\nu} = 0$ (left) or $M_{\nu} = 0.3 \ {\rm eV}$. Here, and in the following plots, we set $\theta_s = 2.4'$, while the different colors refer to the four $z_s$ values.
• Figure 5: Same as Fig. \ref{['fig:cvm_fr4_mv_grids']} but for the fR5 models with $M_{\nu} = (0.10, 0.15) \ {\rm eV}$ respectively in the left and right panels. Beware of the different scale used in the right spider - web plot.