We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Big Three Dragons: A z = 7.15 Lyman-break galaxy detected in [O iii] 88 μm, [C ii] 158 μm, and dust continuum with ALMA.
- Authors
Hashimoto, Takuya; Inoue, Akio K; Mawatari, Ken; Tamura, Yoichi; Matsuo, Hiroshi; Furusawa, Hisanori; Harikane, Yuichi; Shibuya, Takatoshi; Knudsen, Kirsten K; Kohno, Kotaro; Ono, Yoshiaki; Zackrisson, Erik; Okamoto, Takashi; Kashikawa, Nobunari; Oesch, Pascal A; Ouchi, Masami; Ota, Kazuaki; Shimizu, Ikkoh; Taniguchi, Yoshiaki; Umehata, Hideki
- Abstract
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, M UV ≈ −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 T d ≈ 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 L TIR ≈ 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.
- Subjects
HUBBLE Space Telescope (Spacecraft); DUST; STAR formation; STELLAR mass; GALAXIES; INTERPLANETARY dust; STARBURSTS
- Publication
Publications of the Astronomical Society of Japan, 2019, Vol 71, Issue 4, pN.PAG
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psz049