Weinzirl, Tim and Jogee, Shardha and Conselice, Christopher J. and Papovich, Casey and Chary, Ranga-Ram and Bluck, Asa and Grützbauch, Ruth and Buitrago, Fernando and Mobasher, Bahram and Lucas, Ray A. and Dickinson, Mark and Bauer, Amanda E. (2011) Insights on the Formation, Evolution, and Activity of Massive Galaxies from Ultracompact and Disky Galaxies at z = 2-3. Astrophysical Journal, 743 (1). Art. No. 87. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20120203-070059340
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We present our results on the structure and activity of massive galaxies at z = 1-3 using one of the largest (166 with M_* ≥ 5 × 10^(10) M_☉) and most diverse samples of massive galaxies derived from the GOODS-NICMOS survey: (1) Sérsic fits to deep NIC3 F160W images indicate that the rest-frame optical structures of massive galaxies are very different at z = 2-3 compared to z ~ 0. Approximately 40% of massive galaxies are ultracompact (r_e ≤ 2 kpc), compared to less than 1% at z ~ 0. Furthermore, most (~65%) systems at z = 2-3 have a low Sérsic index n ≤ 2, compared to ~13% at z ~ 0. We present evidence that the n ≤ 2 systems at z = 2-3 likely contain prominent disks, unlike most massive z ~ 0 systems. (2) There is a correlation between structure and star formation rates (SFRs). The majority (~85%) of non-active galactic nucleus (AGN) massive galaxies at z = 2-3, with SFR high enough to yield a 5σ (30 μJy) 24 μm Spitzer detection, have low n ≤ 2. Such n ≤ 2 systems host the highest SFR. (3) The frequency of AGNs is ~40% at z = 2-3. Most (~65%) AGN hosts have disky (n ≤ 2) morphologies. Ultracompact galaxies appear quiescent in terms of both AGN activity and star formation. (4) Large stellar surface densities imply massive galaxies at z = 2-3 formed via rapid, highly dissipative events at z > 2. The large fraction of n ≤ 2 disky systems suggests cold mode accretion complements gas-rich major mergers at z > 2. In order for massive galaxies at z = 2-3 to evolve into present-day massive E/S0s, they need to significantly increase (n, r_e). Dry minor and major mergers may play an important role in this process.
|Additional Information:||© 2011 The American Astronomical Society. Received 2011 February 16; accepted 2011 September 22; published 2011 November 23. S.J., C.J.C., T.W., M.D., and R.A.L. acknowledge support from HST grant GO-11082 from STScI, which is operated by AURA, Inc., for NASA, under NAS5-26555. S.J. and T.W. also acknowledge support from the Norman Hackerman Advanced Research Program (NHARP) ARP- 03658-0234-2009, National Aeronautics and Space Administration (NASA) LTSA grant NAG5-13063, and NSF grant AST- 0607748. S.J. and T.W. acknowledge support for this research by the DFG cluster of excellence “Origin and Structure of the Universe” (www.universe-cluster.de). C.J.C. acknowledges support from STFC and the Leverhulme Foundation. We thank Knud Jahnke and Marco Barden for technical assistance with the operation of FERENGI, and Andreas Burkert, Sadegh Khochfar, T. J. Cox, Thorsten Naab, and Ludwig Oser for stimulating discussions. We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr). Some/all of the data presented in this paper were obtained from the Multimission Archive at the Space Telescope Science Institute (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts. The Millennium Galaxy Catalogue consists of imaging data from the Isaac Newton Telescope and spectroscopic data from the Anglo Australian Telescope, the ANU 2.3 m, the ESO New Technology Telescope, the Telescopio Nazionale Galileo, and the Gemini North Telescope. The survey has been supported through grants from the Particle Physics and Astronomy Research Council (UK) and the Australian Research Council (AUS). The data and data products are publicly available from http://www.eso.org/jliske/mgc/ or on request from J. Liske or S.P. Driver.|
|Subject Keywords:||galaxies: evolution; galaxies: formation; galaxies: fundamental parameters; galaxies: interactions; galaxies: structure|
|Official Citation:||Insights on the Formation, Evolution, and Activity of Massive Galaxies from Ultracompact and Disky Galaxies at z = 2–3 Tim Weinzirl et al. 2011 ApJ 743 87|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||03 Feb 2012 15:52|
|Last Modified:||26 Dec 2012 14:47|
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