Gary Mamon's Research Topics: Galaxy Formation

During the last 20 years, astrophysicsts have been developing a good understanding of the general processes describing the formation of galaxies. The general idea is that galaxy disks are built by the accretion of gas, while galaxy bulges and elliptical galaxies are built up by mergers of galaxies of comparable mass. This picture is beginning to change...

Gary Mamon has analytically derived the rate of direct galaxy mergers in clusters of galaxies (Mamon 1992), which has been later confirmed by others with dynamical simulations of merging galaxies.

While this initial work suggested that most elliptical galaxies are the products of mergers, a more refined analysis, based upon high-resolution cosmological simulations of the evolution of dark matter in the Universe, shows that only massive ellipticals acquire the bulk of their mass by mergers, while the majority of low-mass galaxies, including the dwarf ellipticals that dominate the populations of dwarf galaxies within clusters, are not built by mergers (Cattaneo et al. 2011).

Blanchard et al. (1992) were the first to model galaxy formation, assuming that the stellar mass of a galaxy is a simple function of the mass of its (dominant) dark matter halo. Cattaneo et al. (2011) built a more refined model, based upon the physical processes that prevent the accretion of gas onto disks and those that expell the gas from the disks.

Gary Mamon's important papers on the topic are: