Detection of Stacked Filament Lensing Between SDSS Luminous Red Galaxies

Understand

We search for the lensing signal of massive filaments between 135,000 pairs of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey.

• We develop a new estimator that cleanly removes the much larger shear signal of the neighboring LRG halos, relying only on the assumption of spherical symmetry.
• We consider two models: a thick filament model constructed from ray-tracing simulations for $\Lambda$CDM model, and a thin filament model which models the filament by a string of halos along the line connecting the two LRGs.
• We show that the filament lensing signal is in nice agreement with the thick simulation filament, while strongly disfavoring the thin model.