LEAPS-MPS: Constraining Supernova Explosion Models by Alpha Elements in Metal Poor Galaxies and the Intracluster Medium

Once the universe cooled sufficiently for neutral atoms to form (~378,000 years after the Big Bang), its initial chemical composition was limited to hydrogen, helium, and lithium. The other elements in the periodic table necessary for everything from planets to life were all forged over the subsequent 14-billion years in stars, both during their lifetimes and in their cataclysmic self- destruction as supernovae (SNe), with the latter dispersing the newly formed elements. These products can be observed directly via spectroscopy of SNe remnants and stars, as well as the gas filling the space between stars (interstellar medium; ISM) and cluster galaxies (intracluster medium; ICM), and constrain the history of enrichment in the universe. Recent observations of metal poor galaxies, as well as the Perseus cluster ICM, find systematic mismatches between the abundances of alpha elements synthesized in core-collapse (Type II) SNe (i.e., O, Ne, Si, S, Ar, and Ca) and model predictions. The principal investigator (PI) will lead a team of undergraduate researchers to identify the physical processes responsible for this mismatch and develop a new series of SNe models to better account for the observed abundance patterns. The project will recruit underrepresented students for participation in research internships (six per year) and a summer program, as well as enabling public science talks by the PI. The PI and his team will develop a SNe model "pipeline" that includes (1) an advanced stellar evolution code for computing a sequence of massive star models up to the onset of core-collapse, (2) 1-D and multi-dimensional hydrodynamics codes for modeling the explosion phase, and (3) post-processing nucleosynthesis. The team will explore the effects of model parameters such as mixing, explosion energy, and reaction rates, on the production of alpha-elements and use observational data to place constraints on these parameters. They will select the parameter set where the chemical abundances can be well reproduced and use it as a basis to generate a catalogue of stellar models with chemical yields of various parameters, such as the progenitor mass and metallicity. They will also maintain a library of numerical SNe to help astronomers identify the origin of SNe identified by future observatories. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.