ALMA Reveals Potential Evidence for Spiral Arms, Bars, and Rings in High-redshift Submillimeter Galaxies
Journal article, 2019
We present subkiloparsec-scale mapping of the 870 mu m ALMA continuum emission in six luminous (LIR similar to 5 x 10(12 )L(circle dot)) submillimeter galaxies (SMGs) from the ALESS survey of the Extended Chandra Deep Field South. Our high-fidelity 0 ''.07-resolution imaging (similar to 500 pc) reveals robust evidence for structures with deconvolved sizes of less than or similar to 0.5-1 kpc embedded within (dominant) exponential dust disks. The large-scale morphologies of the structures within some of the galaxies show clear curvature and/or clump-like structures bracketing elongated nuclear emission, suggestive of bars, star-forming rings, and spiral arms. In this interpretation, the ratio of the "ring" and "bar" radii (1.9 +/- 0.3) agrees with that measured for such features in local galaxies. These potential spiral/ring/bar structures would be consistent with the idea of tidal disturbances, with their detailed properties implying flat inner rotation curves and Toomre-unstable disks (Q < 1). The inferred one-dimensional velocity dispersions (sigma(r) less than or similar to 70-160 km s(-1)) are marginally consistent with the limits implied if the sizes of the largest structures are comparable to the Jeans length. We create maps of the star formation rate density (Sigma(SFR)) on similar to 500 pc scales and show that the SMGs are able to sustain a given (galaxy-averaged) E-SFR over much larger physical scales than local (ultra)luminous infrared galaxies. However, on 500 pc scales, they do not exceed the Eddington limit set by radiation pressure on dust. If confirmed by kinematics, the potential presence of nonaxisymmetric structures would provide a means for net angular momentum loss and efficient star formation, helping to explain the very high star formation rates measured in SMGs.
submillimeter: galaxies
galaxies: starburst
galaxies: high-redshift
galaxies: evolution
galaxies: formation
Author
J. A. Hodge
Leiden University
I Smail
Durham University
F. Walter
Max Planck Society
E. da Cunha
Australian National University
A. M. Swinbank
Durham University
M. Rybak
Leiden University
B. Venemans
Max Planck Society
W. N. Brandt
Pennsylvania State University
G. Calistro Rivera
Leiden University
S. C. Chapman
Dalhousie University
Chian-Chou Chen
European Southern Observatory Santiago
P. Cox
Centre national de la recherche scientifique (CNRS)
H. Dannerbauer
University of La Laguna
Instituto de Astrofísica de Canarias
R. Decarli
Istituto nazionale di astrofisica (INAF)
T. R. Greve
Technical University of Denmark (DTU)
University of Copenhagen
University College London (UCL)
Kirsten Kraiberg Knudsen
Chalmers, Space, Earth and Environment, Onsala Space Observatory
K. M. Menten
Max Planck Society
E. Schinnerer
Australian National University
J. M. Simpson
Academia Sinica
P. van der Werf
Leiden University
J. L. Wardlow
Lancaster University
A. Weiss
Max Planck Society
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 876 2 130Subject Categories
Astronomy, Astrophysics and Cosmology
Other Physics Topics
Structural Biology
Infrastructure
Onsala Space Observatory
DOI
10.3847/1538-4357/ab1846