A Census of Optical and Near-Infrared Selected Star-Forming and Passively Evolving Galaxies at Redshift Z~2

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dc.creatorReddy, Naveen A.
dc.creatorErb, Dawn K.
dc.creatorSteidel, Charles C.
dc.creatorShapley, Alice E.
dc.creatorAdelberger, Kurt L.
dc.creatorPettini, Max
dc.date2005-07-11
dc.date2005-07-16
dc.date.accessioned2026-07-07T10:43:16Z
dc.date.available2026-07-07T10:43:16Z
dc.descriptionUsing 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 1.4<z<2.6. We find overlap at the 70-80% level in samples of z~2 star-forming galaxies selected by their optical (UGR) and near-IR (BzK) colors when subjected to common K-band limits. Deep Chandra data indicate a 25% AGN fraction among near-IR selected objects, much of which occurs among near-IR bright objects (K<20; Vega). Stacking the X-ray emission for the star-forming galaxies, we find the SFR distributions of UGR, BzK, and J-K>2.3 galaxies (Distant Red Galaxies; DRGs) are very similar as a function of K, with K<20 galaxies having <SFR>~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 1.4<z<2.6 of UGR and BzK galaxies to K=22, and DRGs to K=21 is ~ 0.10+/-0.02 Msun/yr/Mpc^3. Optically-selected galaxies to R=25.5 and K=22 account for ~70% of this total. Of the radio-selected SMGs to S(850 micron)~4 mJy with redshifts 1.4<z<2.6, >80% could be selected by the UGR, BzK, and/or DRG criteria.
dc.description22 pages, 20 figures, accepted to ApJ; change to Table 4
dc.identifierhttps://arxiv.org/abs/astro-ph/0507264
dc.identifierhttp://arxiv.org/abs/astro-ph/0507264
dc.identifierAstrophys.J.633:748-767,2005
dc.identifierdoi:10.1086/444588
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/182179
dc.subjectAstrophysics
dc.titleA Census of Optical and Near-Infrared Selected Star-Forming and Passively Evolving Galaxies at Redshift Z~2
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