Central concentration of warm and dense molecular gas in a strongly lensed submillimeter galaxy at z=6

Akiyoshi Tsujita*, Ken-ichi Tadaki, Kotaro Kohno, Bunyo Hatsukade, Fumi Egusa, Yoichi Tamura, Yuri Nishimura, Jorge Zavala, Toshiki Saito, Hideki Umehata, Minju M. Lee

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

15 Downloads (Pure)

Abstract

We report the detection of the CO(12–11) line emission toward G09-83808 (or H-ATLAS J090045.4+004125), a strongly-lensed submillimeter galaxy at z = 6.02, with Atacama Large Millimeter/submillimeter Array observations. Combining previously detected [O iii] 88 μm, [N ii] 205 μm, and dust continuum at 0.6 mm and 1.5 mm, we investigate the physical properties of the multi-phase interstellar medium in G09-83808. A source-plane reconstruction reveals that the region of the CO(12–11) emission is compact (⁠Re,CO=0.49+0.29−0.19kpc⁠) and roughly coincides with that of the dust continuum. Non-local thermodynamic equilibrium radiative transfer modeling of CO spectral-line energy distribution reveals that most of the CO(12–11) emission comes from a warm (kinetic temperature of Tkin = 320 ± 170 K) and dense [log (nH2/cm−3) = 5.4 ± 0.6] gas, indicating that the warm and dense molecular gas is concentrated in the central 0.5 kpc region. The luminosity ratio in G09-83808 is estimated to be LCO(12-11)/LCO(6-5) = 1.1 ± 0.2. The high ratio is consistent with those in local active galactic nuclei (AGNs) and 6 < z < 7 quasars, the fact of which implies that G09-83808 would be a good target to explore dust-obscured AGNs in the epoch of reionization. In the reconstructed [O iii] 88 μm and [N ii] 205 μm cubes, we also find that a monotonic velocity gradient is extending over the central starburst region by a factor of 2 and that star-forming sub-components exist. High-resolution observations of bright [C ii] 158 μm line emissions will enable us to characterize the kinematics of a possible rotating disk and the nature of the sub-components.
Original languageEnglish
JournalPublication of the Astronomical Society of Japan
Volume74
Issue number6
Pages (from-to)1429–1440
ISSN0004-6264
DOIs
Publication statusPublished - 2022

Keywords

  • Galaxies: high-redshift
  • Galaxies: kinematics and dynamics
  • Galaxies: starburst

Fingerprint

Dive into the research topics of 'Central concentration of warm and dense molecular gas in a strongly lensed submillimeter galaxy at z=6'. Together they form a unique fingerprint.

Cite this