Weak Lensing Measurement of Filamentary Structure with the SDSS BOSS and
  Subaru Hyper Suprime-Cam Data
  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. This
fact demonstrates the statistical power of the HSC survey due to its deep
observations and high number density of source galaxies. Our result is
consistent with the theoretical prediction and supports the "thick" filament
model. As the HSC survey area increases, we will be able to study detailed
filament properties such as the dark matter distributions and redshift
evolution of filaments.
