Dust, its composition and evolution in the Universe

Interstellar dust plays a crucial role in the formation of stars and the evolution and assembly of galaxies. Extinction provides an indirect measure of the enrichment process and conditions within an environment. Using Gamma-ray bursts (GRBs), for the first time, we derive the individual extinction curves of these cosmological sources. We find that their extinction curves are different from the typically used Small Magellanic Cloud type extinction curve. The shape of these extinction curves also provided clues to their grain composition, where more silicate grain population is noticed. Furthermore, looking for dust content in redshift z=0-8 GRBs, we evidenced a real decrease in dust content at z>3.5, suggesting a transition in dust properties and/or available dust building blocks. Below z