Observations of Nearby Galaxies Using SOFIA FIFI-LS Spectroscopy

We report observations of several Far Infrared (FIR) fine structure lines of nearby dwarf galaxies Haro 3, II ZW 40, and NGC 4214 using the Far Infrared Field Imaging-Line Spectrometer (FIFI-LS) onboard SOFIA. These lines are important coolants of the Interstellar Medium (ISM) in galaxies, and in contrast to optical lines are nearly unaffected by extinction from dust, and insensitive to gas temperature, especially in ionized gas (HII) regions. Since the lines trace both the physical properties of the gas (e.g. density, mass, abundances) and the stars (e.g. hardness and strength of the stellar radiations fields), they serve as important tools for understanding star formation and the ISM. We are using FIFI-LS to survey nearby low-metallicity dwarf galaxies specifically, as they have metallicities that are similar to high-redshift galaxies that formed the first generations of stars in the Universe. By studying the relationship between fine structure lines, star formation, and the ISM in these low-metallicity dwarf galaxies, where we are able to cross-reference our results with those from other methods, we will be able to better understand these processes in high redshift galaxies will allow us to better understand star formation over cosmic time.