Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-Era Halo

The SPT0311-58 system at z=6.900 is an extremely massive structure within the reionization epoch, and offers a chance to understand the formation of galaxies in an extreme peak in the primordial density field. We present 70mas Atacama Large Millimeter/submillimeter Array observations of the dust continuum and CII 158um emission in the central pair of galaxies and reach physical resolution ~100-350pc, 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 800Myr 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

Spilker, J. S., Hayward, C. C., Marrone, D. P., Aravena, M., Bethermin, M., Burgoyne, J., ... Weiss, A.

Spilker, Justin S||Hayward, Christopher C||Marrone, Daniel P||Aravena, Manuel||Bethermin, Matthieu||Burgoyne, James||Chapman, Scott C||Greve, Thomas R||Gururajan, Gayathri||Hezaveh, Yashar D||Hill, Ryley||Litke, Katrina C||Lovell, Christopher C||Malkan, Matthew A||Murphy, Eric J||Narayanan, Desika||Phadke, Kedar A||Reuter, Cassie||Stark, Antony A||Sulzenauer, Nikolaus||Vieira, Joaquin D||Vizgan, David||Weiss, Axel

Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-Era Halo Institutional Repository Document