The Impact of Black Hole Formation on Population Averaged Supernova
  Yields
  The landscape of black hole (BH) formation -- which massive stars explode as
core-collapse supernovae (CCSN) and which implode to BHs -- profoundly affects
the IMF-averaged nucleosynthetic yields of a stellar population. Building on
the work of Sukhbold et al. (2016), we compute IMF-averaged yields at solar
metallicity for a wide range of assumptions, including neutrino-driven engine
models with extensive BH formation, models with a simple mass threshold for BH
formation, and a model in which all stars from $8-120 \text{M}_{\odot}$
explode. For plausible choices, the overall yields of $\alpha$-elements span a
factor of three, but changes in relative yields are more subtle, typically
$0.05-0.2$ dex. For constraining the overall level of BH formation, ratios of C
and N to O or Mg are promising diagnostics. For distinguishing complex,
theoretically motivated landscapes from simple mass thresholds, abundance
ratios involving Mn or Ni are promising because of their sensitivity to the
core structure of the CCSN progenitors. We confirm previous findings of a
substantial (factor $2.5-4$) discrepancy between predicted O/Mg yield ratios
and observationally inferred values, implying that models either overproduce O
or underproduce Mg. No landscape choice achieves across-the-board agreement
with observed abundance ratios; the discrepancies offer empirical clues to
aspects of massive star evolution or explosion physics still missing from the
models. We find qualitatively similar results using the massive star yields of
Limongi & Chieffi (2018). We provide tables of IMF-integrated yields for
several landscape scenarios, and more flexible user-designed models can be
implemented through the publicly available $\texttt{Versatile Integrator for
Chemical Evolution}$ ($\texttt{VICE}$; https://pypi.org/project/vice/).
