Pixel Observations of M31 and M33 with MEgacam – POMMME

The Lambda-Cold Dark Matter hierarchical paradigm is robust to large scale observables, and it is on galactic scales that our understanding of the cosmological evolution of matter is most incomplete. Many of the predicted features of galaxies, such as faint satellites and diffuse stellar haloes, are extremely low surface brightness (>31mag/arcsec2). The Milky Way, M31 and M33 are therefore the only three large galaxies in the Universe which can currently provide robust tests of, and constraints on, many fundamental predictions of galaxy formation models. We propose POMMME (Pixel Observations of M31 and M33 with MEgacam), within the Pan-Andromeda Archaeological Survey(PAndAS), which will obtain imaging of over 300 sq.degrees of the M31/M33 sub-group at CFHT. PAndAS will provide the first panoramic view of galaxy haloes over a volume of about 15 million cubic kpc, and will be complete to 32-33 mag per sq. arcsec. PAndAS will provide the deepest and most complete panorama of galaxy haloes available, and will be used to compare to and constrain cosmological models of galaxy formation over an order of magnitude in halo mass. It will be unrivaled by any other extra-galactic wide field survey and will become a benchmark study of nearfield galaxy formation. The legacy value of PAndAS -for M31, M33, the Local Group, dwarf galaxies, globular clusters, stellar populations, galaxy formation and MW structure- is immense. It will become the primary reference dataset for all subsequent studies of the stellar populations of these galaxies, and will remain so into the era of Thirty Meter / ELT Telescopes and beyond.