Graduate Student Seminar with Wolfgang Zober on Galactic Astrophysics

The LIGO observation of a NS merger event and the immediate observational follow-up established neutron star mergers as a site of r-process nucleosynthesis. After this landmark discovery, astrophysicists ask where is the primary site of r-process nucleosynthesis? Is it NS mergers, supernovae and other core-collapse events, a mixture of the two, or is it something more complicated? Our Galactic Cosmic Ray measurements with the balloon borne SuperTIGER gives supports to a model where supernovae in OB associations preferentially accelerate refractory elements that are more readily embedded in interstellar dust grains than volatiles, but this model only holds up to Z=40. The measurements in the Z=41-56 range suggest that there is either a secondary GCR source or that our acceleration model is incorrect. I will talk about how I use ISS-CALET as a check on those measurements through Z=40 and how we plan to out to lead (Z=82) with the recently awarded TIGERISS mission.