The ISM Properties and Gas Kinematics of a Redshift 3 Massive Dusty Star-forming Galaxy

Leung, T. K. Daisy and Riechers, Dominik A. and Baker, Andrew J. and Clements, Dave L. and Cooray, Asantha and Hayward, Christopher C. and Ivison, R. J. and Neri, Roberto and Omont, Alain and Pérez-Fournon, Ismael and Scott, Douglas and Wardlow, Julie L. (2019) The ISM Properties and Gas Kinematics of a Redshift 3 Massive Dusty Star-forming Galaxy. The Astrophysical Journal, 871 (1). ISSN 0004-637X

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Abstract

We present CO (J = 1 → 0 3 → 2 5 → 4 10 → 9) and 1.2 kpc resolution [C II] line observations of the dusty star-forming galaxy (SFG) HXMM05—carried out with the Karl G. Jansky Very Large Array, the Combined Array for Research in Millimeter-wave Astronomy, the Plateau de Bure Interferometer, and the Atacama Large Millimeter/submillimeter Array, measuring an unambiguous redshift of z = 2.9850 ± 0.0009. We find that HXMM05 is a hyperluminous infrared galaxy ({L}IR} = (4 ± 1) × 1013 L ⊙) with a total molecular gas mass of (2.1 ± 0.7) × 1011({α }CO}/0.8) M ⊙. The CO (J = 1 → 0) and [C II] emission are extended over ∼9 kpc in diameter, and the CO line FWHM exceeds 1100 km s‑1. The [C II] emission shows a monotonic velocity gradient consistent with a disk, with a maximum rotation velocity of {v}{{c}} = 616 ± 100 km s‑1 and a dynamical mass of (7.7 ± 3.1) × 1011 M ⊙. We find a star formation rate of 2900{}-595+750 M ⊙ yr‑1. HXMM05 is thus among the most intensely SFGs known at high redshift. Photodissociation region modeling suggests physical conditions similar to nearby SFGs, showing extended star formation, which is consistent with our finding that the gas emission and dust emission are cospatial. Its molecular gas excitation resembles the local major merger Arp 220. The broad CO and [C II] lines and a pair of compact dust nuclei suggest the presence of a late-stage major merger at the center of the extended disk, again reminiscent of Arp 220. The observed gas kinematics and conditions, together with the presence of a companion and the pair of nuclei, suggest that HXMM05 is experiencing multiple mergers as a part of the evolution.

Item Type:
Journal Article
Journal or Publication Title:
The Astrophysical Journal
Additional Information:
This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.3847/1538-4357/aaf860
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
ID Code:
131304
Deposited By:
Deposited On:
18 Feb 2019 12:15
Refereed?:
Yes
Published?:
Published
Last Modified:
18 Sep 2020 04:46