Quantifying the uncertainty on the recent star-formation rate for compact starburst galaxies with fast outflows: evidence for a dusty transition phase?

The universe forms stars inefficiently, and a possible cause is feedback from massive stars. We present results on multiple tracers of the star-formation rate (SFR) for a sample of compact starburst galaxies with fast outflows that are associated with powerful stellar feedback. While their compact and luminous stellar populations indicate extreme values for SFR surface density, these galaxies may be in the process of shutting down their star formation. For galaxies in such a transition phase, different observational SFR tracers may yield different values depending on the underlying assumptions and the timescale on which this shut down of star formation is occurring. We use standard SFR calibrations based on infrared luminosity and emission-line luminosity for these extreme galaxies, and we compare with models of their recent star formation histories. We also quantify the amount of dust attenuation at optical wavelengths and the potential role of escaping ionizing radiation. Finally, we discuss the uncertainties and discrepancies in the measurements of star formation in the last 10 million years and in the last 100 million years for these galaxies. This has important implications for understanding the impact of powerful stellar feedback on star formation in massive galaxies. This work is supported by the National Science Foundation through grant NSF-AST-1813299 to Bates College.