The dependence of galaxy clustering on tidal environment in the Sloan
  Digital Sky Survey
  The influence of the Cosmic Web on galaxy formation and evolution is of great
observational and theoretical interest. We investigate whether the Cosmic Web
leaves an imprint in the spatial clustering of galaxies in the Sloan Digital
Sky Survey (SDSS), using the group catalog of Yang et al. and tidal field
estimates at $\sim2h^{-1}$Mpc scales from the Mass-Tides-Velocity data set of
Wang et al. We use the $\textit{tidal anisotropy}$ $\alpha$ (Paranjape et al.)
to characterise the tidal environment of groups, and measure the redshift-space
2-point correlation function (2pcf) of group positions and the luminosity- and
colour-dependent clustering of group galaxies using samples segregated by
$\alpha$. We find that all the 2pcf measurements depend strongly on $\alpha$,
with factors of $\sim20$ between the large-scale 2pcf of objects in the most
and least isotropic environments. To test whether these strong trends imply
`beyond halo mass' effects for galaxy evolution, we compare our results with
corresponding 2pcf measurements in mock catalogs constructed using a halo
occupation distribution that only uses halo mass as an input. We find that this
prescription qualitatively reproduces $\textit{all}$ observed trends, and also
quantitatively matches many of the observed results. Although there are some
statistically significant differences between our `halo mass only' mocks and
the data -- in the most and least isotropic environments -- which deserve
further investigation, our results suggest that if the tidal environment
induces additional effects on galaxy properties other than those inherited from
their host halos, then these must be weak.
