Presentation #361.03 in the session Stars, Gas, and Dark Matter in Dwarf Galaxies (iPosters).
Far-infrared atomic fine-structure lines can be used to derive gas density, ionization parameter, and gas-phase metallicity in both local and high-z galaxies. A major benefit of far-infrared observation is that it is not affected by dust extinction. NGC 5253 is a local low-metallicity dwarf galaxy. With a combination of SOFIA FIFI-LS and Herschel PACS we obtained data for NGC 5253 and analyzed our data set using both SOSPEX (SOfia SPectral EXplorer) and Python. Each emission line has a slightly differing field of view. Using SOSPEX we have defined an overlapping circular region and extracted the spectra for each line. Then, using Python, we trimmed and subtracted the continuum before fitting to a Gaussian curve in order to determine the flux. Theoretical ionization models suggest that certain line ratios in the far-infrared act as diagnostics for several galactic properties. More specifically, the line ratio of [OIII]88/[OIII]52 is a density diagnostic, [NIII]57/[NII]122 is an ionization diagnostic, and [OIII]88 + [OIII]52/[NIII]57 is a gas-phase metallicity diagnostic. We use Bayesian inference methods to derive these properties. We present our results as well as a thorough comparison with established optical/UV diagnostics.