Gravitational Lensing of the supernovae from the Supernova Legacy Survey
  (SNLS)
  The presence of mass inhomogeneities along the line of sight of propagation
of light fromdistant objects can induce deflection in the flight path of the
photon. This phenomenon is called as gravitational lensing. Lensing can have
both distortion (shear) and isotropic magnification effects on the source. We
studied the effect of lensing magnification on supernova (SN) Ia in this
thesis. Presence of lensing would introduce a source of contamination to the
brightness distribution of the source (SN Ia in our case). Thus it also enables
one to compute the lensing effect indirectly from the Hubble diagram (i.e. from
the residual to the Hubble diagram). In this thesis we computed the correlation
between these two effects : the Hubble residual and the computed lensing
magnification for the SN by the line of sight foreground dark matter haloes. A
detection of positive correlation between these two would signify the
positivity of lensing signal detection. The data sample is the spectroscopic
SNe Ia sample from the five years full SNLS data and the Hubble residuals are
those of the preliminary cosmology analysis performed on SNLS5 data. We obtain
a signal of \rho = 0.177 at 2.51 \sigma. This result is consistent with the
previous SNLS three years data lensing analysis results.
