FLUMEN: Neural Emulator of an Advanced Stochastic Weak Lensing Model — E8 Intelligence Research
Year: 2026
Type: preprint
Abstract: Weak gravitational lensing by intervening structure magnifies distant sources and induces scatter in their luminosity distances. We develop an improved stochastic model for the distribution of weak lensing magnifications, $\textrm{d} P/\textrm{d}μ$, that resolves individual lenses down to $10^7\,M_\odot$ and, besides field halos and filaments, includes subhalos and large-scale clustering of the lens population. Both extensions broaden the distribution, and the resulting scatter in the luminosity distances agrees with the halo-model prediction from the nonlinear matter power spectrum and exceeds that obtained from $N$-body ray tracing, which we attribute to the finite mass resolution and box size of the simulations. Building on this model, we develop \texttt{FLUMEN}, a conditional normalizing-flow emulator that predicts $\textrm{d} P/\textrm{d}μ$ as a function of the source redshift up to $z_s=12$ and six cosmological parameters $\{h,Ω_M,Ω_B,σ_8,n_s,z_{\rm eq}\}$. The emulator enforces Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
Author: Caldin, Andrew Stewart
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225620161