2006ApJ...653.1004R

We present the results of a spectroscopic survey with LRIS-B on Keck of more than 280 star-forming galaxies and AGNs at redshifts 1.4≲z≲3.0 in the GOODS-N field. Candidates are selected by their U_nGR colors using the ``BM/BX'' criteria to target redshift 1.4≲z≲2.5 galaxies and the LBG criteria to target redshift z∼3 galaxies; combined these samples account for ∼25%-30% of the R and K_sband counts to R=25.5 and K_s(AB)=24.4, respectively. The 212 BM/BX galaxies and 74 LBGs constitute the largest spectroscopic sample of galaxies at z>1.4 in GOODS-N. Extensive multiwavelength data allow us to investigate the stellar populations, stellar masses, bolometric luminosities (L_bol), and extinction of z∼2 galaxies. Deep Chandra and Spitzer data indicate that the sample includes galaxies with a wide range in L_bol(≃10¹⁰ to >10¹² L_☉) and 4 orders of magnitude in dust obscuration (L_bol/L_UV). The sample includes galaxies with a large dynamic range in evolutionary state, from very young galaxies (ages ≃50 Myr) with small stellar masses (M^*≃10⁹ M_☉) to evolved galaxies with stellar masses comparable to the most massive galaxies at these redshifts (M^*>10¹¹ M_☉). Spitzer data indicate that the optical sample includes some fraction of the obscured AGN population at high redshifts: at least 3 of 11 AGNs in the z>1.4 sample are undetected in the deep X-ray data but exhibit power-law SEDs longward of ∼2 µm (rest frame) indicative of obscured AGNs. The results of our survey indicate that rest-frame UV selection and spectroscopy presently constitute the most timewise efficient method of culling large samples of high-redshift galaxies with a wide range in intrinsic properties, and the data presented here will add significantly to the multiwavelength legacy of GOODS.