2004ApJ...616L..83G

We measure the star formation rate (SFR) as a function of redshift z up to z~4.5, based on B-, I-, and (I+B)-selected galaxy catalogs from the FORS Deep Field (FDF) and the K-selected catalog from the GOODS-South field. Distances are computed from spectroscopically calibrated photometric redshifts accurate to Δz/(z_spec+1)≤0.03 for the FDF and ≤0.056 for the GOODS-South field. The SFRs are derived from the luminosities at 1500 Å. We find that the total SFR estimates derived from B, I, and I+B catalogs agree very well (≲0.1 dex), while the SFR from the K catalog is lower by ~0.2 dex. We show that the latter is due solely to the lower star-forming activity of K-selected intermediate- and low-luminosity (L<L_*) galaxies. The SFR of bright (L>L_*) galaxies is independent of the selection band, i.e., the same for B-, I-, (I+B)-, and K-selected galaxy samples. At all redshifts, luminous galaxies (L>L_*) contribute only approximately one-third to the total SFR. There is no evidence for significant cosmic variance between the SFRs in the FDF and in the GOODS-South field, ≲0.1 dex, consistent with theoretical expectations. The SFRs derived here are in excellent agreement with previous measurements, provided that we assume the same faint-end slope of the luminosity function as previous works (α~-1.6). However, our deep FDF data indicate a shallower slope of α=-1.07, implying a SFR lower by ~0.3 dex. We find the SFR to be roughly constant up to z~4 and then to decline slowly beyond, if dust extinctions are assumed to be constant with redshift.