Motion of the Local Group as a cosmological probe

Understand

In this thesis, we use the motion of the Local Group of galaxies (LG) through the Universe to measure the cosmological parameter of non-relativistic matter density, Omega_m.

• For that purpose, we compare the peculiar velocity of the LG with its gravitational acceleration.
• The former is known from the dipole of the cosmic microwave background radiation and the latter is estimated here from the clustering dipole of galaxies in the Two Micron All Sky Survey (2MASS) Extended Source Catalog.
• We start by presenting the general framework of perturbation theory of gravitational instability in the expanding Universe and how it applies to the peculiar motion of the LG.