A Census of Optical and Near-Infrared Selected Star-forming and Passively Evolving Galaxies at Redshift z ~ 2*

Using the extensive multiwavelength data in the GOODS-North field, including our ground-based rest-frame UV spectroscopy and near-IR imaging, 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 (UnG) 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 (Ks 2.3 galaxies (i.e., distant red galaxies; DRGs) are very similar as a function of Ks, with Ks 20.5. The absence of X-ray emission from the reddest DRGs and BzK galaxies with (z - K)AB 3 indicates that 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* > 1011 M☉). We consider the contribution of optical, near-IR, and submillimeter selected galaxies to the star formation rate density (SFRD) at z ~ 2, taking into account sample overlap. The SFRD in the interval 1.4 z 2.6 of UnG and BzK galaxies to Ks = 22 and DRGs to Ks = 21 is ~0.10 ± 0.02 M☉ yr-1 Mpc-3. Optically selected galaxies to = 25.5 and Ks = 22.0 account for ~70% of this total. Greater than 80% of radio-selected submillimeter galaxies to S850 μm ~ 4 mJy with redshifts 1.4 < z < 2.6 satisfy either one or more of the BX/BM, BzK, and DRG criteria.

[2]  A. Comastri,et al.  The 2-10 keV luminosity as a Star Formation Rate indicator , 2003 .

[3]  A. Cimatti,et al.  Extremely Red Objects: An X-Ray Dichotomy , 2002, astro-ph/0211305.

[4]  AN 850 MICRON SCUBA SURVEY OF THE HUBBLE DEEP FIELD-NORTH GOODS REGION , 2004, astro-ph/0406261.

[5]  IRAC Mid-Infrared Imaging of the Hubble Deep Field-South: Star Formation Histories and Stellar Masses of Red Galaxies at z > 2* , 2005, astro-ph/0504219.

[6]  A. Moorwood,et al.  Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, , 2003 .

[7]  D. M. Alexander,et al.  The Chandra Deep Field North Survey. XIII. 2 Ms Point-Source Catalogs , 2003, astro-ph/0304392.

[8]  A. Cimatti,et al.  Passively Evolving Early-Type Galaxies at 1.4 ≲ z ≲ 2.5 in the Hubble Ultra Deep Field , 2005, astro-ph/0503102.

[9]  Blair D. Savage,et al.  An IUE Survey of Interstellar H I LY alpha Absorption , 1994 .

[10]  Mark Swinbank,et al.  The Rest-Frame Optical Spectra of SCUBA Galaxies , 2004, astro-ph/0412050.

[11]  Max Pettini,et al.  Optical Selection of Star-forming Galaxies at Redshifts 1 < z < 3 , 2004, astro-ph/0401445.

[12]  I. Hook,et al.  A high abundance of massive galaxies 3–6 billion years after the Big Bang , 2004, Nature.

[13]  M. Giavalisco,et al.  Lyman Break Galaxies at Redshift z ~ 3: Survey Description and Full Data Set , 2003, astro-ph/0305378.

[14]  E. Feigelson,et al.  X-Ray-emitting Young Stars in the Orion Nebula , 2002, astro-ph/0203316.

[15]  A. Kinney,et al.  The Dust Content and Opacity of Actively Star-forming Galaxies , 1999, astro-ph/9911459.

[16]  P. P. van der Werf,et al.  Stellar Populations and Kinematics of Red Galaxies at z > 2: Implications for the Formation of Massive Galaxies , 2004, astro-ph/0404471.

[17]  I. Smail,et al.  A Redshift Survey of the Submillimeter Galaxy Population , 2004, astro-ph/0412573.

[18]  C. C. Steidel,et al.  Multiwavelength Observations of Dusty Star Formation at Low and High Redshift , 2000, astro-ph/0001126.

[19]  Stephen S. Eikenberry,et al.  A Wide-Field Infrared Camera for the Palomar 200-inch Telescope , 2003, SPIE Astronomical Telescopes + Instrumentation.

[20]  C. Steidel,et al.  Evidence for Solar Metallicities in Massive Star-forming Galaxies at z ≳ 2 , 2004, astro-ph/0405187.

[21]  T. M. Heckman,et al.  A High Spatial Resolution X-Ray and Hα Study of Hot Gas in the Halos of Star-forming Disk Galaxies. II. Quantifying Supernova Feedback , 2003, astro-ph/0306598.

[22]  T. Heckman,et al.  The Starburst Nature of Lyman Break Galaxies: Testing Ultraviolet Extinction with X-Rays , 2002, astro-ph/0204047.

[23]  Caltech,et al.  X-ray properties of UV-selected star-forming galaxies at z ∼ 1 in the Hubble Deep Field North , 2005, astro-ph/0501411.

[24]  D. M. Alexander,et al.  Optical and Infrared Properties of the 2 Ms Chandra Deep Field North X-Ray Sources , 2003, astro-ph/0306212.

[25]  Strong Spatial Clustering of Ultraviolet-selected Galaxies with Magnitude Ks < 20.5 and Redshift z ~ 2* , 2005, astro-ph/0501354.

[26]  Timothy M. Heckman,et al.  The host galaxies of active galactic nuclei , 2003 .

[27]  Timothy M. Heckman,et al.  Dust Absorption and the Ultraviolet Luminosity Density at z ≈ 3 as Calibrated by Local Starburst Galaxies , 1999, astro-ph/9903054.

[28]  A. Cimatti,et al.  The K20 survey - III. Photometric and spectroscopic properties of the sample , 2002, astro-ph/0206168.

[29]  P. P. van der Werf,et al.  A Substantial Population of Red Galaxies at z > 2: Modeling of the Spectral Energy Distributions of an Extended Sample , 2004, astro-ph/0408077.

[30]  M. Giavalisco,et al.  The Great Observatories Origins Deep Survey: Initial results from optical and near-infrared imaging , 2003, astro-ph/0309105.

[31]  G. Wilson,et al.  Infrared Properties of Radio-selected Submillimeter Galaxies in the Spitzer First Look Survey Verification Field , 2004 .

[32]  W. Brandt,et al.  The X-Ray Spectral Properties of SCUBA Galaxies , 2005, astro-ph/0506608.

[33]  E. Feigelson,et al.  The Chandra Deep Survey of the Hubble Deep Field-North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area , 2001 .

[34]  M. Pettini,et al.  A Survey of Star-forming Galaxies in the 1.4 ≲ z ≲ 2.5 Redshift Desert: Overview , 2004, astro-ph/0401439.

[35]  P. P. van der Werf,et al.  Chandra Constraints on the Active Galactic Nucleus Fraction and Star Formation Rate of Red z ≳ 2 Galaxies in the FIRES MS 1054–03 Field , 2004, astro-ph/0408101.

[36]  Patrick J. McCarthy,et al.  The Gemini Deep Deep Survey. I. Introduction to the Survey, Catalogs, and Composite Spectra , 2004, astro-ph/0402436.

[37]  P. P. van der Werf,et al.  Spectroscopic Confirmation of a Substantial Population of Luminous Red Galaxies at Redshifts z ≳ 2 , 2003, astro-ph/0303166.

[38]  Carl Heiles,et al.  The bell laboratories H I survey , 1992 .

[39]  A. Cimatti,et al.  The K20 survey - IV. The redshift distribution of $K_{\rm s}<20$ galaxies: A test of galaxy formation models , 2002, astro-ph/0207191.

[40]  P. P. van der Werf,et al.  A Significant Population of Red, Near-Infrared-selected High-Redshift Galaxies , 2003, astro-ph/0303163.

[41]  A. Cimatti,et al.  Near-Infrared Bright Galaxies at z ≃ 2. Entering the Spheroid Formation Epoch? , 2003, astro-ph/0308456.

[42]  M. Giavalisco,et al.  A Deep Wide-Field, Optical, and Near-Infrared Catalog of a Large Area around the Hubble Deep Field North , 2003, astro-ph/0312635.

[43]  M. Halpern,et al.  The Hubble Deep Field North SCUBA Super-map—I. Submillimetre maps, sources and number counts , 2003, astro-ph/0305444.

[44]  C. Steidel,et al.  X-Ray and Radio Emission from Ultraviolet-selected Star-forming Galaxies at Redshifts 1.5 ≲ z ≲ 3.0 in the GOODS-North Field , 2004, astro-ph/0401432.

[45]  G. Bruzual,et al.  Stellar population synthesis at the resolution of 2003 , 2003, astro-ph/0309134.

[46]  The Host Galaxies of AGN , 2003, astro-ph/0304239.

[47]  Harland W. Epps,et al.  THE KECK LOW-RESOLUTION IMAGING SPECTROMETER , 1995 .

[48]  STAR FORMATION IN GALAXIES ALONG THE HUBBLE SEQUENCE , 1998, astro-ph/9807187.

[49]  R. Sunyaev,et al.  The Milky Way in X-rays for an outside observer , 2001, astro-ph/0109239.

[50]  Old galaxies in the young Universe , 2004, Nature.

[51]  S. M. Fall,et al.  High-Redshift Extremely Red Objects in the Hubble Space Telescope Ultra Deep Field Revealed by the GOODS Infrared Array Camera Observations , 2004, astro-ph/0408070.

[52]  A. Cimatti,et al.  A New Photometric Technique for the Joint Selection of Star-forming and Passive Galaxies at 1.4 <~ z <~ 2.5 , 2004, astro-ph/0409041.