Dependence of GAMA galaxy halo masses on the cosmic web environment from
  100 square degrees of KiDS weak lensing data
  Galaxies and their dark matter haloes are part of a complex network of mass
structures, collectively called the cosmic web. Using the tidal tensor
prescription these structures can be classified into four cosmic environments:
voids, sheets, filaments and knots. As the cosmic web may influence the
formation and evolution of dark matter haloes and the galaxies they host, we
aim to study the effect of these cosmic environments on the average mass of
galactic haloes. To this end we measure the galaxy-galaxy lensing profile of
91,195 galaxies, within 0.039 < z < 0.263, from the spectroscopic Galaxy And
Mass Assembly (GAMA) survey, using ~100 square degrees of overlapping data from
the Kilo-Degree Survey (KiDS). In each of the four cosmic environments we model
the contributions from group centrals, satellites and neighbouring groups to
the stacked galaxy-galaxy lensing profiles. After correcting the lens samples
for differences in the stellar mass distribution, we find no dependence of the
average halo mass of central galaxies on their cosmic environment. We do find a
significant increase in the average contribution of neighbouring groups to the
lensing profile in increasingly dense cosmic environments. We show, however,
that the observed effect can be entirely attributed to the galaxy density at
much smaller scales (within 4 Mpc/h), which is correlated with the density of
the cosmic environments. Within our current uncertainties we find no direct
dependence of galaxy halo mass on their cosmic environment.
