The nature of the [C II] emission in dusty star-forming galaxies from the SPT survey

B. Gullberg, C. De Breuck, J. D. Vieira, A. Weiß, J. E. Aguirre, M. Aravena, M. Béthermin, C. M. Bradford, M. S. Bothwell, J. E. Carlstrom, S. C. Chapman, C. D. Fassnacht, A. H. Gonzalez, T. R. Greve, Y. Hezaveh, W. L. Holzapfel, K. Husband, J. Ma, M. Malkan, Daniel P MarroneK. Menten, E. J. Murphy, C. L. Reichardt, J. S. Spilker, A. A. Stark, M. Strandet, N. Welikala

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63 Scopus citations

Abstract

We present [C II] observations of 20 strongly lensed dusty star-forming galaxies at 2.1 < z < 5.7 using Atacama Pathfinder EXperiment and Herschel. The sources were selected on their 1.4 mm flux (S1.4mm > 20 mJy) from the South Pole Telescope (SPT) survey, with far-infrared (FIR) luminosities determined from extensive photometric data. The [CII] line is robustly detected in 17 sources, all but one being spectrally resolved. 11 out of 20 sources observed in [C II] also have low-J CO detections from Australia Telescope Compact Array. A comparison with mid- and high-J CO lines from Atacama Large Millimeter/submillimeter Array reveals consistent [C II] and CO velocity profiles, suggesting that there is little differential lensing between these species. The [C II], low-J CO and FIR data allow us to constrain the properties of the interstellar medium. We find [C II] to CO(1-0) luminosity ratios in the SPT sample of 5200 ± 1800, with significantly less scatter than in other samples. This line ratio can be best described by a medium of [C II] and CO emitting gas with a higher [C II] than CO excitation temperature, high CO optical depth τ CO(1-0) ≫ 1, and low to moderate [CII] optical depth τ[C II]≲ 1. The geometric structure of photodissociation regions allows for such conditions.

Original languageEnglish (US)
Pages (from-to)2883-2900
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume449
Issue number3
DOIs
Publication statusPublished - 2015

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Keywords

  • Galaxies: high-redshift
  • Galaxies: ISM
  • Galaxies: starburst
  • Infrared: galaxies
  • Submillimetre: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Gullberg, B., De Breuck, C., Vieira, J. D., Weiß, A., Aguirre, J. E., Aravena, M., ... Welikala, N. (2015). The nature of the [C II] emission in dusty star-forming galaxies from the SPT survey. Monthly Notices of the Royal Astronomical Society, 449(3), 2883-2900. https://doi.org/10.1093/mnras/stv372