LAM Seminar: Pierre-Alain Duc “From UDGs to UCDs via dE,Ns and HST to Euclid; a history of the evolution of dwarf galaxies and their surveys”

As the most numerous galaxies in the Universe, with an expected number depending on the cosmology, dwarf galaxies attract a great deal of attention. However, outside the Local Group and nearby clusters, they are difficult to identify because their low surface brightness makes them morphologically very similar to distant background spirals or ellipticals, while determining their distance from spectroscopic data remains particularly difficult. However, with the advent of large-scale deep imaging surveys such as MATLAS, DES, and most recently Euclid, large catalogues of candidate dwarf galaxies have become available. These will allow us not only to estimate the faint end of the luminosity function and constrain cosmology, but also to learn about the formation and evolution of galaxies.
Dwarf galaxies come 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 space data from HST and Euclid, I will review recent results showing possible evolutionary links between these classes of intriguing objects.
Prospects for the analysis of future surveys will be discussed.