Gaia will play an important role in providing information about star formation histories , merging events , intergalactic streams etc. , for nearby galaxies of the Local Group .
One of the most crucial contributions will be proper motions , especially for stars in the outermost parts of the galaxies , obtainable for stellar populations to \sim 150 kpc with RGB stars .
Together with radial velocities for the brightest giants ( < 80 kpc ) , this will provide membership information for individual stars and global kinematical picture of the most nearby galaxies , including the Magellanic Clouds ( MCs ) .
Gaia will also provide photometric metallicities ( \sigma ( [ M / H ] ) < 0.3 ) for individual giants and/or supergiants in dwarf galaxies to \sim 200 kpc .
MSTO ages will be possible for the youngest stellar populations in the most nearby galaxies ( e.g. , MCs ) , whereas stars on RGB/AGB may provide age estimates for populations to \sim 150 kpc .
Gaia will allow to study the outermost parts of the galaxies , which ( because of their large spatial extent ) are difficult to assess from the ground .
Apart from allowing to clarify the structure and evolution of the dwarf galaxies , this will also make it possible to investigate galactic tidal debris , thus providing additional details for the global picture of formation and evolution of the Milky Way Galaxy .