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Unveil the stellar halo distribution with multi-wavelength photometry

Guillaume THOMAS, NRC Herzberg Astronomy & Astrophysics, Victoria, Canada

The stellar halo of our Galaxy is mostly formed by stars that were initially lying in dwarf galaxies and globular clusters, which have been disrupted by the tidal field of the Milky Way. Therefore, due to the long survivability of the structures created by these disruptions, the stellar halo is the best place to probe the accretion history of our Galaxy.

I will present recent works that was made using in particular the new deep u-band component of the Canada-France-Imaging Survey (CFIS), in combinaison to other surveys, such as Pan-STARRS 1 or Gaia. With these observations, it have been possible to study the stellar halo with different type of stars, such as the Blue Horizontal Branch stars (BHBs). More recently, we developed a machine learning based algorithm that disantangle the giants from the dwarfs, and that obtain their distance and metallicity with a high precision, using only their photometry. This new dataset will be extremely valuable for future studies of the stellar halo of the Milky Way, based on different stellar populations. I will also present a novative method to compare directly cosmological simulations to large photometric observations.