Spatially Resolved [C ii] Emission in SPT0346-52: A Hyper-starburst Galaxy Merger at z ∼ 5.7

Katrina C. Litke, Daniel P. Marrone, Justin S. Spilker, Manuel Aravena, Matthieu Béthermin, Scott Chapman, Chian Chou Chen, Carlos De Breuck, Chenxing Dong, Anthony Gonzalez, Thomas R. Greve, Christopher C. Hayward, Yashar Hezaveh, Sreevani Jarugula, Jingzhe Ma, Warren Morningstar, Desika Narayanan, Kedar Phadke, Cassie Reuter, Joaquin VieiraAxel Weiss

Research output: Contribution to journalArticlepeer-review


SPT0346-52 is one of the most most luminous and intensely star-forming galaxies in the universe, with LFIR > 1013 L 13 and Σ SFR ≈ 4200 M yr-1 kpc -2. In this paper, we present ∼0.′15 ALMA observations of the [C II] 158 μm emission line in this z = 5.7 dusty star-forming galaxy. We use a pixellated lensing reconstruction code to spatially and kinematically resolve the source-plane [C II] and rest-frame 158 ?m dust continuum structure at ∼700 pc (∼0.′ 12) resolution. We discuss the [C II] deficit with a pixellated study of the L[C II]/LFIR ratio in the source plane. We find that individual pixels within the galaxy follow the same trend found using unresolved observations of other galaxies, indicating that the deficit arises on scales ≲700 pc. The lensing reconstruction reveals two spatially and kinematically separated components (∼1 kpc and ∼500 km s-1 apart) connected by a bridge of gas. Both components are found to be globally unstable, with Toomre Q instability parameters ≪1 everywhere. We argue that SPT0346-52 is undergoing a major merger, which is likely driving the intense and compact star formation.

Original languageEnglish (US)
Article number80
JournalAstrophysical Journal
Issue number2
StatePublished - Jan 10 2019


  • galaxies: high-redshift
  • galaxies: starburst

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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