Large-Scale Filaments From Weak Lensing

Abstract

In the context of non-linear structure formation, a web of dark filaments are expected to intersect the high density regions of the universe, where groups and clusters of galaxies will be forming. In this work we have developed a method for stacking the weak lensing signal of an ensemble of filaments between groups and clusters of galaxies. We detect a the weak lensing signal from stacked filaments between SDSS BOSS luminous red galaxies with the CFHTLenS data at the 5σ level, finding a mass of (1.6 ± 0.3) × 1013M⊙. Two methods of isolating the filament signal are presented: the method of non-physical pair subtraction, and the method of outside region subtraction. This signal is compared with the three-point galaxy-galaxy-convergence correlation function, as developed in Clampitt et al. (2014), yielding reasonably good agreement.