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The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift

Gullberg, B.; Swinbank, A.M.; Smail, I.; Biggs, A.D.; Bertoldi, F.; Breuck, C. De; Chapman, S.C.; Chen, C.-C.; Cooke, E.A.; Coppin, K.E.K.; Cox, P.; Dannerbauer, H.; Dunlop, J.S.; Edge, A.C.; Farrah, D.; Geach, J.E.; Greve, T.R.; Hodge, J.; Ibar, E.; Ivison, R.J.; Karim, A.; Schinnerer, E.; Scott, D.; Simpson, J.M.; Stach, S.M.; Thomson, A.P.; van der Werf, P.; Walter, F.; Wardlow, J.L.; Weiss, A.

The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift Thumbnail


Authors

B. Gullberg

A.M. Swinbank

A.D. Biggs

F. Bertoldi

C. De Breuck

S.C. Chapman

C.-C. Chen

E.A. Cooke

K.E.K. Coppin

P. Cox

H. Dannerbauer

J.S. Dunlop

D. Farrah

J.E. Geach

T.R. Greve

J. Hodge

E. Ibar

R.J. Ivison

A. Karim

E. Schinnerer

D. Scott

J.M. Simpson

S.M. Stach

A.P. Thomson

P. van der Werf

F. Walter

J.L. Wardlow

A. Weiss



Abstract

We present deep, high-resolution (0 03, 200 pc) ALMA Band 7 observations covering the dust continuum and [C II] λ157.7 μm emission in four z ∼ 4.4–4.8 sub-millimeter galaxies (SMGs) selected from the ALESS and AS2UDS surveys. The data show that the rest-frame 160 μm (observed 345 GHz) dust emission is consistent with smooth morphologies on kpc scales for three of the sources. One source, UDS 47.0, displays apparent substructure, but this is also consistent with a smooth morphology—as indicated by simulations showing that smooth exponential disks can appear clumpy when observed at the high angular resolution (0 03) and depth of these observations (s345 GHz ~ 27 47 – μJy beam−1 ). The four SMGs are bright [C II] emitters. We extract [C II] spectra from the high-resolution data, and recover ∼20%–100% of the [C II] flux and ∼40%–80% of the dust continuum emission, compared to the previous lower-resolution observations. When tapered to 0 2 resolution, our maps recover ∼80%–100% of the continuum emission, indicating that ∼60% of the emission is resolved out on ∼200 pc scales. We find that the [C II] emission in high-redshift galaxies is more spatially extended than the rest-frame 160 μm dust continuum by a factor of 1.6 ± 0.4. By considering the L[ ] C II /LFIR ratio as a function of the star formation rate surface density (SSFR), we revisit the [C II] deficit and suggest that the decline in the L[ ] C II /LFIR ratio as a function of SSFR is consistent with local processes. We also explore the physical drivers that may be responsible for these trends and can give rise to the properties found in the densest regions of SMGs.

Citation

Gullberg, B., Swinbank, A., Smail, I., Biggs, A., Bertoldi, F., Breuck, C. D., …Weiss, A. (2018). The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift. Astrophysical Journal, 859(1), Article 12. https://doi.org/10.3847/1538-4357/aabe8c

Journal Article Type Article
Acceptance Date Apr 9, 2018
Online Publication Date May 17, 2018
Publication Date May 17, 2018
Deposit Date Jun 7, 2018
Publicly Available Date Jun 8, 2018
Journal Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 859
Issue 1
Article Number 12
DOI https://doi.org/10.3847/1538-4357/aabe8c

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Copyright Statement
© 2018. The American Astronomical Society. All rights reserved.





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