Analyzing Far-IR [O III] and [C II] Emission Using SOFIA in Highly-Ionized Local Galaxies.

The nearby, highly-ionized, and metal-poor dwarf galaxies (z < 0.1) are the best analogs to comprehend high-redshift galaxies due to their proximity and similarity in stellar content. In this work, we seek to answer the question, do we see local analogs to be elevated in [O III] 88 µm compared to [C II] 157 µm similar to the high-redshift systems (z > 6) for which there are ALMA observations of [O III] + [C II]? We used the SOFIA telescope to collect data for a four galaxy sample, chosen based on a high-ionization UV spectrum similar to z > 6 galaxies. We study the emission of [O III] and [C II], strong nebular lines, from the Interstellar Medium (ISM) and analyze it with the star-formation rate (SFR) and metallicity of local analogs. [C II] was detected in three systems which indicated that these systems are not suppressed as observed in z > 6 galaxies and the fluxes were consistent with the correlation found with SFR in the Dwarf Galaxy Survey (DGS). We examined the [O III]/[C II] flux ratios and found them to be consistent with DGS data but lower than ALMA constraints in z > 6 galaxies. We speculate that there are strong lower ionization lines in the photodissociation regions in the local analog, due to how ISM is structured, compared to z > 6 galaxies.