SYGMA: Stellar Yields for Galactic Modeling Applications
  The stellar yields for galactic modeling applications (SYGMA) code is an
open-source module that models the chemical ejecta and feedback of simple
stellar populations (SSPs). It is intended for use in hydrodynamical
simulations and semi-analytic models of galactic chemical evolution. The module
includes the enrichment from asymptotic giant branch (AGB) stars, massive
stars, SNIa and neutron-star mergers. An extensive and extendable stellar
yields library includes the NuGrid yields with all elements and many isotopes
up to Bi. Stellar feedback from mechanic and frequency-dependent radiative
luminosities are computed based on NuGrid stellar models and their synthetic
spectra. The module further allows for customizable initial-mass functions and
supernova Ia (SNIa) delay-time distributions to calculate time-dependent ejecta
based on stellar yield input. A variety of r-process sites can be included. A
comparison of SSP ejecta based on NuGrid yields with those from Portinari et
al. (1998) and Marigo (2001) reveals up to a factor of 3.5 and 4.8 less C and N
enrichment from AGB stars at low metallicity, a result we attribute to NuGrid's
modeling of hot-bottom burning. Different core-collapse supernova explosion and
fallback prescriptions may lead to substantial variations for the accumulated
ejecta of C, O and Si in the first $10^7\, \mathrm{yr}$ at $Z=0.001$. An online
interface of the open-source SYGMA module enables interactive simulations,
analysis and data extraction of the evolution of all species formed by the
evolution of simple stellar populations.
