Speaker
Description
At the conclusion of SDSS-IV, the APOGEE Stellar Parameters and Chemical Abundance Pipeline (ASPCAP) still had a few limitations that impacted the ability to use its results for some scientific applications. In this talk, I will summarize progress investigating and finding solutions for two of these limitations: (1) measurement of weak lines, like Ce and Nd (Hayes et al. 2022) and (2) the determination of upper-limits on the measurable abundances for low-metallicity stars (Shetrone et al., in prep.). I will describe our solution to these limitations and the implementation in post-ASPCAP analyses. I will show two of the studies only enabled by this work (1) Ce/Nd ratios that trace the evolution of the r- and s- process within the MW (Hayes et al. in prep) and (2) the metallicity distribution functions at low [Fe/H]. The former provides insight into the overall chemical evolution for neutron capture elements. The latter allows comparisons of the metallicity distributions for 11 dwarf galaxies (Bootes, Draco, Sextans, Carina, Sculptor, Ursa Minor, Fornax, Large Magellanic Cloud, Small Magellanic Cloud, Sagittarius, GES/GSE) with the individual Milky Way components over several orders of magnitude in mass on the same underlying abundance system -- for the first time. I will describe our next steps toward realizing heretofore infeasible results from DR17 and the potential impact to SDSS-V. This presentation argues that there are still many improvements to the traditional ASPCAP analysis that can open up exciting scientific investigations.
