ALMA detections of [O III] and [C II] emission lines from A1689-zD1 at z = 7.13

Wong, Yi Hang Valerie and Wang, Poya and Hashimoto, Tetsuya and Takagi, Toshinobu and Goto, Tomotsugu and Kim, Seong Jin and Wu, Cossas K.-W. and On, Alvina Y. L. and Santos, Daryl Joe D. and Lu, Ting-Yi and Kilerci, Ece and Ho, Simon C.-C. and Hsiao, Tiger Y.-Y. (2022) ALMA detections of [O III] and [C II] emission lines from A1689-zD1 at z = 7.13. Astrophysical Journal, 929 (2). ISSN 0004-637X (Print) 1538-4357 (Online)

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A1689-zD1 is one of the most distant galaxies, discovered with the aid of gravitational lensing, providing us with an important opportunity to study galaxy formation in the very early universe. In this study, we report the detection of [C ii]158 μm and [O iii]88 μm emission lines of A1689-zD1 in the Atacama Large Millimeter/submillimeter Array (ALMA) Bands 6 and 8. We measure the redshift of this galaxy as z sys = 7.133 ± 0.005 based on the [C ii] and [O iii] emission lines, consistent with that adopted by Bakx et al. The observed L [O III]/L [C II] ratio is 2.09 ± 0.09, higher than that of most of the local galaxies, but consistent with other z ∼7 galaxies. The moderate spatial resolution of ALMA data provided us with a precious opportunity to investigate spatial variation of L [O III]/L [C II]. In contrast to the average value of 2.09, we find a much higher L [O III]/L [C II] of ∼7 at the center of the galaxy. This spatial variation of L [O III]/L [C II] was seldom reported for other high-z galaxies. It is also interesting that the peak of the ratio does not overlap with optical peaks. Possible physical reasons include a central active galactic nucleus, shock heating from merging, and a starburst. Our moderate spatial resolution data also reveal that in addition to the observed two clumps shown in previous Hubble Space Telescope images, there is a redshifted segment to the west of the northern optical clump. This structure is consistent with previous claims that A1689-zD1 is a merging galaxy, but with the northern redshifted part being some ejected material, or that the northern redshifted material stems from a third more highly obscured region of the galaxy. © 2022. The Author(s).
Item Type: Article
Subjects: Q Science > QB Astronomy > QB460-466 Astrophysics
Divisions: Faculty of Engineering and Natural Sciences
Depositing User: Ece Kilerci
Date Deposited: 30 Jun 2022 14:58
Last Modified: 22 Aug 2022 13:02

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