Panchromatic Estimation of Star Formation Rates in BzK Galaxies at 1<z<3

TL;DR

This study estimates star formation rates in BzK-selected galaxies at redshifts 1 to 3 using multi-wavelength stacking analyses, finding consistent SFR indicators and cautioning against sole reliance on 24 micron or X-ray estimates.

Contribution

It introduces a comprehensive panchromatic approach combining IR, UV, radio, and X-ray data to accurately estimate SFRs in high-redshift galaxies, improving calibration reliability.

Findings

SFR(IR+UV) estimates are consistent within errors across methods.

Average SFRs increase with redshift, reaching up to 154 Msun/yr at z~2.2.

24 micron and X-ray based SFRs should be used cautiously at high redshift.

Abstract

We determine star formation rates (SFRs) in a sample of color-selected, star-forming (sBzK) galaxies (K(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 micron, UV, radio and X-ray wavebands. We find consistency with our best estimator, SFR(IR+UV), to within errors for the preferred radio SFR calibration. Our results imply that 24 micron 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(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 Msun yr^-1 respectively, with additional systematic uncertainty of a factor of ~2.