PANCHROMATIC ESTIMATION OF STAR FORMATION RATES IN BzK GALAXIES AT 1 < z < 3

Abstract

We determine star formation rates (SFRs) in a sample of color-selected, star-forming (sBzK) galaxies (K [subscript AB] < 21.8) in the Extended Chandra Deep Field-South. To identify and avoid active galactic nuclei, we use X-ray, IRAC color, and IR/radio flux ratio selection methods. Photometric redshift-binned, average flux densities are measured with stacking analyses in Spitzer-MIPS IR, BLAST and APEX/LABOCA submillimeter, VLA and GMRT radio, and Chandra X-ray data. We include averages of aperture fluxes in MUSYC UBVRIz'JHK images to determine UV-through-radio spectral energy distributions. We determine the total IR luminosities and compare SFR calibrations from FIR, 24 μm, UV, radio, and X-ray wavebands. We find consistency with our best estimator, SFR[subscript IR + UV], to within errors for the preferred radio SFR calibration. Our results imply that 24 μm only and X-ray SFR estimates should be applied to high-redshift galaxies with caution. Average IR luminosities are consistent with luminous infrared galaxies. We find SFR[subscript IR + UV] for our stacked sBzKs at median redshifts 1.4, 1.8, and 2.2 to be 55 ± 6 (random error), 74 ± 8, and 154 ± 17 M [subscript ☉] yr[superscript –1], respectively, with additional systematic uncertainty of a factor of ~2.