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Galactic Archaeology: decoding the fossil record of Galaxy formation and evolution

Sede A. Riccò Via Santa Sofia 78, Catania

One of most important issue in Astrophysics is the achievement of a robust understanding of the sequence of processes that contributed to the building up of the Milky Way. This is obviously important not only "on a local scale" in order to recover the history of formation and evolution of the Galaxy, but also, more in general, for understanding the formation process of spiral galaxies. In the last decade, the advent of high precision photometric and spectroscopic surveys as well as the possibility to estimate, thanks to the ESA Gaia mission, accurate distance for a huge number of field stars, combined with the development of an accurate theoretical framework, is actually opening a new era for this kind of investigations.
We will present some recent results - obtained by using this updated observational and theoretical framework - about the formation and early evolution of the Milky Way.

Status and future of 21-cm cosmology during the first billion years

Sede A. Riccò Via Santa Sofia 78, Catania

The 21-cm hyperfine line of neutral hydrogen is set to revolutionize studies of the first billion years, spanning the cosmic dawn of the first stars and eventual reionization of our Universe. I will discuss the potential of this probe in learning about the unknown astrophysics of the first galaxies as well as physical cosmology. Current upper limits on the cosmic 21-cm power spectrum already provide new insights into the heating of the intergalactic medium, and the X-ray sources in the first galaxies. I will discuss the upcoming steps, including the main challenges, that will eventually lead to the Nobel prize-worthy 3D map of half of our observable Universe with the Square Kilometer Array (SKA) telescope.