Correlations between multiple tracers of the cosmic web
  The large-scale structure of the Universe is a cosmic web of interconnected
clusters, filaments, and sheets of matter. This PhD comprises two complementary
projects investigating the cosmic web using correlations between three
different tracers: the cosmic microwave background (CMB), supernovae (SNe), and
large quasar groups (LQGs). In the first project we re-analyse the apparent
correlation between CMB temperature and SNe redshift reported by Yershov, Orlov
and Raikov. They presented evidence that the WMAP/Planck CMB pixel-temperatures
at SNe locations tend to increase with increasing redshift. They suggest this
could be caused by the Integrated Sachs-Wolfe effect and/or by residual
foreground contamination. Our analysis supports the prima facie existence of
the correlation but attributes it instead to a composite selection bias caused
by the chance alignment of seven deep survey fields with CMB hotspots. These
seven fields contain just 9.2% of the SNe sample. We estimate the likelihood of
their falling on CMB hotspots by chance is approximately 1 in 11. In the second
project we investigate for the first time the apparent coherent alignment of
LQGs in the redshift range 1.0 <= z <= 1.8. We find that the position angles
(PAs) of LQGs are correlated, specifically aligned and orthogonal, with a
maximum significance of ~2.4 sigma at typical angular (comoving) separations of
~30 degrees (~1.6 Gpc). Spatial coincidence between our LQG sample and regions
of quasar polarization alignment first reported by Hutsemekers, and the
similarity between LQG PAs and radio polarization angles reported by Pelgrims
and Hutsemekers, suggest an interesting result.
