Giovedì 12 marzo alle ore 15:00 Francesca Annibali (INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna) terrà un seminario dal titolo “Building Dwarf Galaxies from the Bottom Up: Evidence for Dwarf–Dwarf Mergers in the Nearby Universe”.

ABSTRACT:
Although interactions and mergers are a fundamental component of the commonly accepted Lambda CDM paradigm, direct observational evidence of accretion events around otherwise isolated dwarf galaxies is still very poor. In this talk I will present the results of a project aimed at characterizing streams and tidal features around dwarf galaxies in order to understand how they build-up from hierarchical merging of smaller units. The project builds on a program at the Large Binocular Telescope providing wide-field, deep imaging for 45 nearby (D<10 Mpc) dwarf galaxies with the aim of identifying tidal features down to unprecedented low surface brightness limits. From these data, convincing signatures of recent interaction with smaller companions have been found in six systems. Deep, follow-up HST observations have then been acquired for the interacting dwarfs in order to infer their star formation histories (SFHs) in detail through resolved-star color magnitude diagram modeling. In the end, the derived SFHs will provide, together with the galaxies’ kinematical and morphological properties, crucial constraints for N-body hydrodynamical simulations aimed at reconstructing the host-satellite merging histories. I will conclude my talk discussing future perspectives opened up by the recently started Euclid mission in the framework of merging phenomena in low mass galaxies.