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D.B. Haarsma (Calvin College), R.B. Partridge (Haverford College), R.A. Windhorst, E.A. Richards (Arizona State)
The radio luminosity of nearby galaxies correlates well with their star formation rate. When this relationship is applied to high-redshift radio sources, we can estimate the global star formation history of the universe. Radio observations are not affected by dust extinction, unlike optical and ultraviolet determinations of star formation history which require uncertain corrections for dust. Faint radio sources, detected in deep radio surveys of the Hubble Deep Field North and other fields, tend to be associated with spiral galaxies rather than ellipticals and AGN. Using redshift information for these sources, we can estimate the evolution of the luminosity function, and from that estimate the global star formation history. At redshifts less than one, our calculated star formation rates are significantly larger than most dust-corrected optically-selected star formation rates; however, we confirm the rapid rise from z=0 to z=1 seen in those surveys.
We acknowledge support from the National Science Foundation.