Galactic Archeology: Looking for Ghosts in the Galactic Halo, Luis Aguilar (UNAM)

The most accepted cosmological model (Lambda-CDM),  predicts that galaxies like ours are built up from fusions of smaller structures. To test this idea, the best place is the galactic halo, where dynamical times are largest and phase mixing is slow in erasing traces of past accretion events.
Although firm evidence of structure in our halo has been found, to really test the cosmological model, it is necessary to have a census, complete within well defined limits, rather than serendipitous discoveries. This requires a high precision, deep survey of the halo.
ESA will launch in 2012 the GAIA astrometric mission. It will make an all sky survey up to magnitude 22, with an astrometric precision orders of magnitude better than Hipparcos. Gaia promises to give us, for the first time, a glimpse of the phase space distribution of stars for a significant fraction of the Galaxy.
In this work, we present results from an thorough study aimed at finding the limits of what we will be able to do, in terms of identifying substructure in the galactic halo, using the Gaia catalogue. Studies like these are necessary to prepare the path for an efficient and fruitful harvesting of the Gaia database. Its unprecedented precision and unbiased coverage warrant the use of novel techniques.