Weak Lensing Measurement of Filamentary Structure with the SDSS BOSS and Subaru Hyper Suprime-Cam Data

Understand

We report the weak lensing measurement of filaments between Sloan Digital Sky Survey (SDSS) III/Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxy pairs at $z\sim0.55$, using the Subaru Hyper Suprime-Cam (HSC) first-year galaxy shape catalogue.

• Despite of the small overlap of $140$ deg$^2$ between these surveys we detect the filament lensing signal at 3.9$\sigma$ significance, which is the highest signal-to-noise lensing measurement of filaments between galaxy-scale halos at this redshift range.
• We derive a theoretical prediction and covariance using mock catalogues based on full-sky ray-tracing simulations.
• We find that the intrinsic scatter of filament properties and the fluctuations in large scale structure along the line-of-sight are the primary component of the covariance and the intrinsic shape noise from source galaxies no longer limits our lensing measurement.