Journal article · Preprint article
ALMA Reveals Potential Evidence for Spiral Arms, Bars, and Rings in High-redshift Submillimeter Galaxies
Leiden University1
National Institute for Astrophysics2
National Space Institute, Technical University of Denmark3
Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark4
Chalmers University of Technology5
Max Planck Institute for Radio Astronomy6
Academia Sinica - Institute of Astronomy and Astrophysics7
Lancaster University8
Durham University9
Max Planck Institute for Astronomy10
Australian National University11
Pennsylvania State University12
Dalhousie University13
European Southern Observatory14
Institut d’Astrophysique de Paris15
Instituto de Astrofísica de Canarias16
...and 6 moreWe present subkiloparsec-scale mapping of the 870 μm ALMA continuum emission in six luminous (LIR ∼ 5 × 1012L⊙) submillimeter galaxies (SMGs) from the ALESS survey of the Extended Chandra Deep Field South. Our high-fidelity 0.″07-resolution imaging (∼500 pc) reveals robust evidence for structures with deconvolved sizes of ≲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 (σr ≲ 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 (ΣSFR) on ∼500 pc scales and show that the SMGs are able to sustain a given (galaxy-averaged) ΣSFR 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.
Language: | English |
---|---|
Year: | 2019 |
Pages: | 130 |
ISSN: | 15384357 , 0004637x , 15384365 and 00670049 |
Types: | Journal article and Preprint article |
DOI: | 10.3847/1538-4357/ab1846 |
ORCIDs: | Greve, T. R. , 0000-0001-6586-8845 , 0000-0003-3037-257X , 0000-0003-4793-7880 , 0000-0001-9759-4797 , 0000-0003-1192-5837 , 0000-0002-1383-0746 , 0000-0001-9024-8322 , 0000-0002-0167-2453 , 0000-0002-3805-0789 , 0000-0001-7147-3575 , 0000-0002-2662-8803 , 0000-0002-7821-8873 , 0000-0001-6459-0669 , 0000-0002-3933-7677 , 0000-0002-8521-1995 , 0000-0001-5434-5942 and 0000-0003-4678-3939 |