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.

galaxies: evolution

galaxies: starburst

galaxies: high-redshift

submillimeter: galaxies

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 Astrofisico de Canarias

R. Decarli

INAF OAS Bologna

T. R. Greve

University College London (UCL)

University of Copenhagen

Technical University of Denmark (DTU)

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 2 130

Subject Categories

Astronomy, Astrophysics and Cosmology

Other Physics Topics

Structural Biology

Infrastructure

Onsala Space Observatory

DOI

10.3847/1538-4357/ab1846

More information

Latest update

7/16/2019