Faint and peculiar objects in GAIA: results from GSC-II
  The one billion objects in the GSC-II make up a formidable data set for the hunt of peculiar and rare targets such as late type stars, white dwarfs, carbon dwarfs, asteroids, variable stars, etc. Here we present a survey to search for ancient cool white dwarfs, which led to the discovery of several stars with peculiar spectral distributions and extreme physical properties. Finally, we discuss the impact of the GAIA mission with respect to these peculiar and faint white dwarfs. 
D. Carollo, A. Spagna, M.G. Lattanzi, S.T. Hodgkin, R.L. Smart, B.   McLean