A Census of Optical and Near‐Infrared Selected Star‐forming and Passively Evolving Galaxies at Redshiftz∼ 2

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Abstract
Using the extensive multi-wavelength data in the GOODS-North field, we construct and draw comparisons between samples of optical and near-IR selected star-forming and passively evolving galaxies at redshifts 1.42.3 galaxies (Distant Red Galaxies; DRGs) are very similar as a function of K, with K~120 Msun/yr, a factor of two to three higher than those with K>20.5. The absence of X-ray emission from the reddest DRGs and BzK galaxies with z-K>3 indicates they must have declining star formation histories to explain their red colors and low SFRs. While the M/L ratio of passively-evolving galaxies may be larger on average, the Spitzer/IRAC data indicate that their inferred stellar masses do not exceed the range spanned by optically selected galaxies, suggesting that the disparity in current SFR may not indicate a fundamental difference between optical and near-IR selected massive galaxies (M* > 10^11 Msun). We consider the contribution of UGR, BzK, DRG, and submillimeter galaxies (SMGs) to the SFRD at z~2, taking into account sample overlap. The total SFRD in the interval 1.480% could be selected by the UGR, BzK, and/or DRG criteria.Comment: 22 pages, 20 figures, accepted to ApJ; change to Table