Multiwavelength Observations of Dusty Star Formation at Low and High Redshift

If high-redshift galaxies resemble rapidly star-forming galaxies in the local universe, most of the luminosity produced by their massive stars will have been absorbed by dust and re-radiated as far-infrared photons that cannot be detected with existing facilities. This paper examines what can be learned about high-redshift star formation from the small fraction of high-redshift galaxies ’ luminosities that is emitted at accessible wavelengths. We first consider the most basic ingredient in the analysis of high-redshift surveys: the estimation of star-formation rates for detected galaxies. Standard techniques require an estimate of the bolometric luminosity produced by their massive stars. We review and quantify empirical correlations between bolometric luminosities produced by star formation and the UV, mid-IR, sub-mm, and radio luminosities of galaxies in the local universe. These correlations suggest that observations of high-redshift galaxies at any of these wavelengths should constrain their star-formation rates to within ∼ 0.2–0.3 dex. We assemble the limited evidence that high-redshift galaxies obey these locally calibrated correlations. The second part of the paper