Theoretical Modeling of Star-Forming Galaxies I. Emission Line
  Diagnostic Grids for Local and Low-Metallicity Galaxies
  We use the newest generation of the Starburst99/Mappings code to generate an
extensive suite of models to facilitate detailed studies of star-forming
galaxies and their ISM properties, particularly at low metallicities. The new
models used include a rigorous treatment of metal opacities in the population
synthesis modeling and more detailed dust physics in the photoionization code.
These models span a wide range of physical parameters including metallicity,
ionization parameter, and the adoption of both a instantaneous burst and
continuous star formation history. We examine the agreement between our models
and local (z < 0.1) star-forming galaxy populations from several large
datasets, including the Sloan Digital Sky Survey, the Nearby Field Galaxy
Survey, and samples of blue compact galaxies and metal-poor galaxies. We find
that models adopting a continuous star formation history reproduce the
metallicity-sensitive line ratios observed in the local population of
star-forming galaxies, including the low-metallicity sample. However, we find
that the current codes generate an insufficiently hard ionizing radiation
field, leading to deficiencies in the [SII] fluxes produced by the models. We
consider the advantages and short-comings of this suite of models, and discuss
future work and improvements that can be applied to the modeling of
star-forming galaxies.
