|Speaker||Talk Date||Talk Series|
|Andrea Ferrara, Scuola Normale Superiore, Pisa||7 May 2009||Institute of Astronomy Colloquia|
After the Bing Bang the cosmic gas had a composition
which was (virtually) free of heavy elements. Yet, every single parcel
of gas that we can probe today with our most powerful telescopes
shows the signs of considerable amounts of metals, up to the highest redshifts. When these metals where first produced, by what sources, and how these atomic species traveled away from their production sites are among the most challenging puzzles in current cosmological scenarios. I will discuss the open problems and the corresponding experimental data in detail. I will then propose viable explanations that eventually might results in a coherent picture of the history of cosmic metal enrichment.