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arXiv · 1811.07800

Spatially Resolved [CII] 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 Vieira·Axel Weiß
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Abstract

SPT0346-52 is one of the most most luminous and intensely star-forming galaxies in the universe, with L_FIR > 10^13 L_sol and Sigma_SFR ~ 4200 M_sol yr^-1 kpc^-2. In this paper, we present ~0.15'' ALMA observations of the [CII]158micron 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 [CII] and rest-frame 158 micron dust continuum structure at ~700 pc (~0.12'') resolution. We discuss the [CII] deficit with a pixellated study of the L_[CII]/L_FIR 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.

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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 Vieira, Axel Weiß. 2018-11-19. Spatially Resolved [CII] Emission in SPT0346-52: A Hyper-Starburst Galaxy Merger at z~5.7. https://doi.org/10.3847/1538-4357%2Faaf057

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