“From UDGs to UCDs via dE,Ns; evidence of star cluster migration and merger in dwarf galaxies”
As the most numerous galaxies in the Universe, with an expected number depending on the cosmology, dwarf galaxies attract a lot of attention. However, outside the local group and galaxy clusters, they are difficult to identify, even in the nearby Universe, because their size and low surface brightness make them very similar to distant background spirals or ellipticals. However, with the advent of large-scale deep imaging surveys such as MATLAS, DES, Euclid and LSST, large catalogues of candidate dwarf galaxies have become available. They will allow us not only to constrain cosmology, but also, in the first place, to understand their structure and morphological evolution. Dwarf galaxies come indeed in a wide variety of types and properties: irregular or elliptical, ultra-compact or ultra-diffuse, nucleated or not, globular cluster rich or not, dark matter rich or poor. Using data obtained with HST and Euclid, I will review recent results showing possible evolutionary links between these classes of objects.