文章基本信息

标题：ALMA Deep Field in SSA22
其他标题：A near-infrared-dark submillimeter galaxy atz= 4.0
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作者：Hideki Umehata ; Ian Smail ; A. M. Swinbank 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：640
页码：1-7
DOI：10.1051/0004-6361/202038146
语种：English
出版社：EDP Sciences
摘要：Deep surveys with the Atacama Large Millimeter Array (ALMA) have uncovered a population of dusty star-forming galaxies which are faint or even undetected at optical to near-infrared wavelengths. Their faintness at short wavelengths makes the detailed characterization of the population challenging. Here we present a spectroscopic redshift identification and a characterization of one of these near-infrared-dark galaxies discovered by an ALMA deep survey. The detection of [C I](1–0) and CO(4–3) emission lines determines the precise redshift of the galaxy, ADF22.A2, to bez = 3.9913 ± 0.0008. On the basis of a multi-wavelength analysis, ADF22.A2 is found to be a massive, star-forming galaxy with a stellar mass ofM∗= 1.1−0.6+1.3× 1011M⊙and SFR = 430−150+230 M⊙yr−1. The molecular gas mass was derived to beM(H2)[CI] = (5.9 ± 1.5)×1010 M⊙, indicating a gas fraction of ≈35%, and the ratios ofL[CI](1−0)/LIRandL[CI](1−0)/LCO(4−3)suggest that the nature of the interstellar medium in ADF22.A2 is in accordance with those of other bright submillimeter galaxies. The properties of ADF22.A2, including the redshift, star-formation rate, stellar mass, and depletion time scale (τdep ≈ 0.1−0.2 Gyr), also suggest that ADF22.A2 has the characteristics expected for the progenitors of quiescent galaxies atz ≳ 3. Our results demonstrate the power of ALMA contiguous mapping and line scan, which help us to obtain an unbiased view of galaxy formation in the early Universe.
关键词：ensubmillimeter: galaxiesgalaxies: starburstgalaxies: high-redshiftsubmillimeter: ISMgalaxies: evolution