Colloquium by Alex Ji, University of Chicago
The dwarf galaxies around the Milky Way provide a promising laboratory for studying nucleosynthesis and galaxy formation. They span a wide range of stellar masses and star formation histories, so the chemical abundances of their stars preserve a variety of different chemical signatures. In this talk, I will focus on elements synthesized in the rapid neutron-capture process (r-process), which is responsible for cosmic production of elements like gold, platinum, and uranium. Though the astrophysical origin of r-process elements has been debated for decades, it is now clear that they must be synthesized in rare events like neutron star mergers or collapsars. I will show that the rarity of the r-process can be used to demonstrate the presence of bursty star formation in the smallest dwarf galaxies, while the variety of dwarf galaxy formation histories can place constraints on the delay timescale of the r-process. Overall, dwarf galaxies show that both prompt and delayed sources of r-process elements are needed, and their relative importance depends on the specific environment and time under consideration.
Followed by wine and cheese.
Host: Greg Bryan