Le 17 mai 2019
De 10h30 à 12h00
Giuseppina Battaglia
Instituto de Astrofísica de Canarias
The dwarf galaxies inhabiting the Local Group (LG) can be studied from a currently unique perspective, that of resolved stellar populations. It is for these systems that with present-day facilities we can obtain information on their lifetime star formation histories (SFHs) and wide-area chemical and internal kinematic properties with a level of detail impossible elsewhere. The majority of dwarf galaxies in the LG are found to be satellites of the Milky Way or M31, thus it is likely that their evolution and present-day properties are the result of interplay between internal and environmental mechanisms. In order to leverage the role of environment, I will present a comparison of the properties of isolated versus satellite dwarf galaxies in the LG, based on a combination of deep photometry and wide-area spectroscopic samples of individual stars from 8m-class telescopes. In addition, the second data release from the Gaia mission has given the unprecedented opportunity to determine 3D systemic motions for the great majority of the dwarf galaxies and candidate galaxies found within 400kpc from the Milky Way, a crucial information to understand the properties of these systems. We have timely exploited this possibility and performed such determination for 43 Milky Way satellites; 32 of them did not have systemic proper motions before. I will present results from this analysis, exploring connections between the objects’ orbital and present-day properties, as well the origin of these systems as Milky Way satellites or satellites of the LMC. Finally, I will also present recent insights on the occurrence of accretion/merging events on the smallest galactic scales as revealed by wide-area photometric and kinematic data-sets.