Catholic University of America
Using SOFIA/FIFI-LS to explore the properties of high-redshift galaxies
With the SOFIA/FIFI-LS instrument it is possible to probe the ionized gas in local galaxies using a suite of far-infrared fine-structure lines. The benefits of using diagnostic lines in the far-infrared are that extinction corrections are negligible. There are, however, additional benefits. Simultaneously having data from optical/UV diagnostic lines and far-infrared lines, probing the same interstellar gas, allows a comparison of various diagnostic lines to assess their suitability in deriving gas characteristics. The same far-infrared fine-structure lines that can be observed with SOFIA/FIFI-LS can be observed at high redshifts with ALMA, as seen in a number of recent results. Several large programs targeting fine-structure lines in high-z galaxies is either on-going or planned with ALMA. The limitations with the ALMA observations is that only a few fine-structure lines are accessible at a given redshift due to atmospheric absorption. Results obtained at low redshifts with SOFIA/FIFI-LS can therefore aid in the interpretation of the high-z results, and may be critical for inferring the properties of the high-z galaxies. I will present some recent results obtained with SOFIA/FIFI-LS on local analogs to high-z galaxies. These are metal-poor star-forming dwarf galaxies, and discuss desired upgrades and improvements to the spectroscopic capabilities of SOFIAS with these results in mind.