Kiloparsec-Scale Dust Disks in High-Redshift Luminous Submillimeter Galaxies
Journal article, 2016
We present high-resolution (0 ''.6) 870 mu m Atacama Large Millimeter/submillimeter Array (ALMA) imaging of 16 luminous (LIR similar to 4 x 10(12) L-circle dot) submillimeter galaxies (SMGs) from the ALESS survey of the Extended Chandra Deep Field South. This dust imaging traces the dust-obscured star formation in these z similar to 2.5 galaxies on similar to 1.3 kpc scales. The emission has a median effective radius of R-e = 0 ''.24 +/- 0 ''.02, corresponding to a typical physical size of R-e= 1.8 +/- 0.2 kpc. We derive a median Sersic index of n = 0.9 +/- 0.2, implying that the dust emission is remarkably disk-like at the current resolution and sensitivity. We use different weighting schemes with the visibilities to search for clumps on 0 ''.12. (similar to 1.0 kpc) scales, but we find no significant evidence for clumping in the majority of cases. Indeed, we demonstrate using simulations that the observed morphologies are generally consistent with smooth exponential disks, suggesting that caution should be exercised when identifying candidate clumps in even moderate signal-to-noise ratio interferometric data. We compare our maps to comparable-resolution Hubble Space Telescope H-160-band images, finding that the stellar morphologies appear significantly more extended and disturbed, and suggesting that major mergers may be responsible for driving the formation of the compact dust disks we observe. The stark contrast between the obscured and unobscured morphologies may also have implications for SED fitting routines that assume the dust is co-located with the optical/near-IR continuum emission. Finally, we discuss the potential of the current bursts of star formation to transform the observed galaxy sizes and light profiles, showing that the z similar to 0 descendants of these SMGs are expected to have stellar masses, effective radii, and gas surface densities consistent with the most compact massive (M* similar to 1-2 x 10(11) M-circle dot) early-type galaxies observed locally.
submillimeter: galaxies
galaxies: high-redshift
galaxies: starburst
galaxies: evolution
galaxies: formation
Author
J. A. Hodge
Leiden University
A. M. Swinbank
Durham University
J. M. Simpson
University of Edinburgh
I. Smail
Durham University
F. Walter
Max Planck Society
D. M. Alexander
Durham University
F. Bertoldi
University of Bonn
A. D. Biggs
European Southern Observatory (ESO)
W. N. Brandt
Pennsylvania State University
S. C. Chapman
Dalhousie University
C. C. Chen
Durham University
K. E. K. Coppin
McGill University
P. Cox
Atacama Large Millimeter-submillimeter Array (ALMA)
H. Dannerbauer
University of Vienna
Instituto de Astrofísica de Canarias
A. C. Edge
Durham University
T. R. Greve
University College London (UCL)
R. J. Ivison
University of Edinburgh
Royal Observatory
A. Karim
University of Bonn
Kirsten Kraiberg Knudsen
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
K. M. Menten
University of Bonn
H. W. Rix
Max Planck Society
E. Schinnerer
Max Planck Society
J. L. Wardlow
Durham University
A. Weiss
Max Planck Society
P. van der Werf
Leiden University
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 833 1 103Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
DOI
10.3847/1538-4357/833/1/103