Effect of gravitational lens

mortsell2001b showed that the effects of gravitational lens increase the dispersion of the luminosity to the maximum of the supernovæ. This effect is all the more significant as the shift towards the red is significant.

The authors showed that for a redshift around 1, the systematic effects could be of the same order of magnitude as the intrinsic dispersion of the supernovæ.

knop2003 showed starting from simulations that the systematic effects on the determination of $\Omega _ { \rm M}$ are a shift of 0.01 with a dispersion of 0.01. The batch used has a shift towards the average red of about 0.6.