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Constraint on the Assembly and Dynamics of Galaxies. II. Properties of Kiloparsec-Scale Clumps in Rest-Frame Optical Emission of z ~ 2 Star-Forming Galaxies

Förster Schreiber, N. M. and Shapley, A. E. and Genzel, R. and Bouché, N. and Cresci, G. and Davies, R. and Erb, D. K. and Genel, S. and Lutz, D. and Newman, S. and Shapiro, K. L. and Steidel, C. C. and Sternberg, A. and Tacconi, L. J. (2011) Constraint on the Assembly and Dynamics of Galaxies. II. Properties of Kiloparsec-Scale Clumps in Rest-Frame Optical Emission of z ~ 2 Star-Forming Galaxies. Astrophysical Journal, 739 (1). Art. No. 45. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20110930-113320403

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Abstract

We study the properties of luminous stellar "clumps" identified in deep, high-resolution Hubble Space Telescope NIC2/F160W imaging at 1.6 μm of six z ~ 2 star-forming galaxies with existing near-infrared integral field spectroscopy from SINFONI at the Very Large Telescope. Individual clumps contribute ~0.5%-15% of the galaxy-integrated rest-frame ≈5000 Å emission, with median of ≈2%; the total contribution of clump light ranges from 10% to 25%. The median intrinsic clump size and stellar mass are ~1 kpc and ~10^9 M_☉, in the ranges for clumps identified in rest-UV or line emission in other studies. The clump sizes and masses in the subset of disks are broadly consistent with expectations for clump formation through gravitational instabilities in gas-rich, turbulent disks given the host galaxies' global properties. By combining the NIC2 data with Advanced Camera for Surveys (ACS)/F814W imaging available for one source, and adaptive-optics-assisted SINFONI Hα data for another, we infer modest color, M/L, and stellar age variations within each galaxy. In these two objects, sets of clumps identified at different wavelengths do not fully overlap; NIC2-identified clumps tend to be redder/older than ACS- or Hα-identified clumps without rest-frame optical counterparts. There is evidence for a systematic trend of older ages at smaller galactocentric radii among the clumps, consistent with scenarios where inward migration of clumps transports material toward the central regions. From constraints on a bulge-like component at radii ≾1-3 kpc, none of the five disks in our sample appears to contain a compact massive stellar core, and we do not discern a trend of bulge stellar mass fraction with stellar age of the galaxy. Further observations are necessary to probe the buildup of stellar bulges and the role of clumps in this process.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0004-637X/739/1/45DOIArticle
http://iopscience.iop.org/0004-637X/739/1/45PublisherArticle
ORCID:
AuthorORCID
Shapley, A. E.0000-0003-3509-4855
Genzel, R.0000-0002-2767-9653
Erb, D. K.0000-0001-9714-2758
Genel, S.0000-0002-3185-1540
Lutz, D.0000-0003-0291-9582
Steidel, C. C.0000-0002-4834-7260
Tacconi, L. J.0000-0002-1485-9401
Additional Information:© 2011 The American Astronomical Society. Received 2011 April 1; accepted 2011 July 4; published 2011 September 6. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program no. 10924. Also based on observations obtained at the Very Large Telescope of the European Southern Observatory, Paranal, Chile (ESO Programme IDs 073.B-9018, 074.A-9011, 075.A-0466, 076.A-0527, 077.A-0576, 078.A-0600, 079.A-0341, 080.A-0330, and 080.A-0339). We are grateful to our many colleagues for stimulating discussions and insightful comments on various aspects of this work, in particular A. Burkert, P. Johansson, T. Naab, A. Renzini, S. Wuyts, and the entire SINS team. We also wish to thank M. Swinbank and T. Jones for useful discussions and additional information about clumps in their lensed galaxy samples. We thank the referee for a thoughtful report and useful suggestions that improved the presentation of the results. Support for HST program no. 10924 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. N.M.F.S. acknowledges support by the Minerva program of the MPG. A.E.S. acknowledges support from the David and Lucile Packard Foundation. N.B. is supported by the Marie Curie grant PIOF-GA-2009-236012 from the European Commission. G.C. acknowledges support by ASI-INAF grant I/009/10/0. A.S. thanks the DFG for support via German-Israeli Project Cooperation Grant STE1868/1-1.GE625/15.1.
Funders:
Funding AgencyGrant Number
NASA10924
NASANAS 5-26555
David and Lucile Packard FoundationUNSPECIFIED
Marie Curie FellowshipPIOF-GA-2009-236012
Agenzia Spaziale Italiana (ASI)I/009/10/0
Deutsche Forschungsgemeinschaft (DFG)STE1868/1-1.GE625/15.1
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: high-redshift; galaxies: structure; infrared: galaxies
Issue or Number:1
Classification Code:PACS: 98.62.Ai; 98.62.Ck; 98.62.Py; 98.70.Lt
Record Number:CaltechAUTHORS:20110930-113320403
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20110930-113320403
Official Citation:Constraints on the Assembly and Dynamics of Galaxies. II. Properties of Kiloparsec-scale Clumps in Rest-frame Optical Emission of z ~ 2 Star-forming Galaxies N. M. Förster Schreiber et al. 2011 ApJ 739 45
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:25511
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:03 Oct 2011 15:00
Last Modified:04 Dec 2019 23:02

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