%AHashimoto, Takuya [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan, Department of Environmental Science and Technology, Faculty of Design Technology, Osaka Sangyo University, 3-1-1 Nagaito, Daito, Osaka 574-8530, Japan, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan]%AHashimoto, Takuya%AInoue, Akio [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan, Department of Environmental Science and Technology, Faculty of Design Technology, Osaka Sangyo University, 3-1-1 Nagaito, Daito, Osaka 574-8530, Japan]%AInoue, Akio%AMawatari, Ken%AMawatari, Ken [Department of Environmental Science and Technology, Faculty of Design Technology, Osaka Sangyo University, 3-1-1 Nagaito, Daito, Osaka 574-8530, Japan, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan]%ATamura, Yoichi [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan]%ATamura, Yoichi%AMatsuo, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan, Department of Astronomical Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan]%AMatsuo, Hiroshi%AFurusawa, Hisanori%AFurusawa, Hisanori [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan]%AHarikane, Yuichi%AHarikane, Yuichi [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan, Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan]%AShibuya, Takatoshi%AShibuya, Takatoshi [Department of Computer Science, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan]%AKnudsen, Kirsten%AKnudsen, Kirsten [Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden]%AKohno, Kotaro%AKohno, Kotaro [Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan, Research Center for the Early Universe, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan]%AOno, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan]%AOno, Yoshiaki%AZackrisson, Erik%AZackrisson, Erik [Observational Astrophysics, Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden]%AOkamoto, Takashi%AOkamoto, Takashi [Department of Cosmosciences, Graduates School of Science, Hokakido University, N10 W8, Kitaku, Sapporo, Hokkaido 060-0810, Japan]%AKashikawa, Nobunari%AKashikawa, Nobunari [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan, Department of Astronomical Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan, Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan]%AOesch, Pascal%AOesch, Pascal [Geneva Observatory, University of Geneva, Ch. des Maillettes, 51, 1290 Versoix, Switzerland]%AOuchi, Masami [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan, Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan]%AOuchi, Masami%AOta, Kazuaki [Kyoto University Research Administration Office, Yoshida-Honmachi, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan]%AOta, Kazuaki%AShimizu, Ikkoh%AShimizu, Ikkoh [Theoretical Astrophysics, Department of Earth & Space Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan]%ATaniguchi, Yoshiaki [The Open University of Japan, 2-11 Wakaba, Mihama-ku, Chiba, Chiba 261-8586, Japan]%ATaniguchi, Yoshiaki%AUmehata, Hideki%AUmehata, Hideki [The Open University of Japan, 2-11 Wakaba, Mihama-ku, Chiba, Chiba 261-8586, Japan, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako-shi, Saitama, Saitama 351-0198, Japan]%AWatson, Darach%AWatson, Darach [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, 4. sal, DK-2100 Copenhagen, Denmark]%BJournal Name: Publications of the Astronomical Society of Japan; Journal Volume: 71; Journal Issue: 4; Related Information: CHORUS Timestamp: 2023-12-21 10:36:50 %D2019%IOxford University Press %JJournal Name: Publications of the Astronomical Society of Japan; Journal Volume: 71; Journal Issue: 4; Related Information: CHORUS Timestamp: 2023-12-21 10:36:50 %K %MOSTI ID: 10103468 %PMedium: X %TBig Three Dragons: A z = 7.15 Lyman-break galaxy detected in [O  iii ] 88 μm, [C  ii ] 158 μm, and dust continuum with ALMA %XAbstract

We present new ALMA observations and physical properties of a Lyman break galaxy at z = 7.15. Our target, B14-65666, has a bright ultra-violet (UV) absolute magnitude, MUV ≈ −22.4, and has been spectroscopically identified in Lyα with a small rest-frame equivalent width of ≈4 Å. A previous Hubble Space TElescope (HST) image has shown that the target is composed of two spatially separated clumps in the rest-frame UV. With ALMA, we have newly detected spatially resolved [O iii] 88 μm, [C ii] 158 μm, and their underlying dust continuum emission. In the whole system of B14-65666, the [O iii] and [C ii] lines have consistent redshifts of 7.1520 ± 0.0003, and the [O iii] luminosity, (34.4 ± 4.1) × 108 L⊙, is about three times higher than the [C ii] luminosity, (11.0 ± 1.4) × 108 L⊙. With our two continuum flux densities, the dust temperature is constrained to be Td ≈ 50–60 K under the assumption of a dust emissivity index of βd = 2.0–1.5, leading to a large total infrared luminosity of LTIR ≈ 1 × 1012 L⊙. Owing to our high spatial resolution data, we show that the [O iii] and [C ii] emission can be spatially decomposed into two clumps associated with the two rest-frame UV clumps whose spectra are kinematically separated by ≈200 km s−1. We also find these two clumps have comparable UV, infrared, [O iii], and [C ii] luminosities. Based on these results, we argue that B14-65666 is a starburst galaxy induced by a major merger. The merger interpretation is also supported by the large specific star formation rate (defined as the star formation rate per unit stellar mass), sSFR $= 260^{+119}_{-57}\:$Gyr−1, inferred from our SED fitting. Probably, a strong UV radiation field caused by intense star formation contributes to its high dust temperature and the [O iii]-to-[C ii] luminosity ratio.

%0Journal Article