Spilker, Justin S. and Hayward, Christopher C. and Marrone, Daniel P. and Aravena, Manuel and Béthermin, Matthieu and Burgoyne, James and Chapman, Scott C. and Greve, Thomas R. and Gururajan, Gayathri and Hezaveh, Yashar D. and Hill, Ryley and Litke, Katrina C. and Lovell, Christopher C. and Malkan, Matthew A. and Murphy, Eric J. and Narayanan, Desika and Phadke, Kedar A. and Reuter, Cassie and Stark, Antony A. and Sulzenauer, Nikolaus and Vieira, Joaquin D. and Vizgan, David and Weiß, Axel (2022) Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-era Halo. The Astrophysical Journal Letters, 929 (1). L3. ISSN 2041-8205
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Abstract
The SPT 0311–58 system at z = 6.900 is an extremely massive structure within the reionization epoch and offers a chance to understand the formation of galaxies at an extreme peak in the primordial density field. We present 70 mas Atacama Large Millimeter/submillimeter Array observations of the dust continuum and [C ii] 158 μm emission in the central pair of galaxies and reach physical resolutions of ∼100–350 pc, among the most detailed views of any reionization-era system to date. The observations resolve the source into at least a dozen kiloparsec-size clumps. The global kinematics and high turbulent velocity dispersion within the galaxies present a striking contrast to recent claims of dynamically cold thin-disk kinematics in some dusty galaxies just 800 Myr later at z ∼ 4. We speculate that both gravitational interactions and fragmentation from massive parent disks have likely played a role in the overall dynamics and formation of clumps in the system. Each clump individually is comparable in mass to other 6 < z < 8 galaxies identified in rest-UV/optical deep field surveys, but with star formation rates elevated by a factor of ~3-5. Internally, the clumps themselves bear close resemblance to greatly scaled-up versions of virialized cloud-scale structures identified in low-redshift galaxies. Our observations are qualitatively similar to the chaotic and clumpy assembly within massive halos seen in simulations of high-redshift galaxies.
Item Type: | Article |
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Subjects: | Euro Archives > Physics and Astronomy |
Depositing User: | Managing Editor |
Date Deposited: | 29 Apr 2023 04:06 |
Last Modified: | 19 Jan 2024 10:48 |
URI: | http://publish7promo.com/id/eprint/2408 |