ALMA Deep Field in SSA22
ALMA Deep Field in SSA22
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DOI：
10.1051/0004-6361/202038146
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发表时间：
2020-07
影响因子：
6.5
通讯作者：
H. Umehata;I. Smail;A. M. Swinbank;K. Kohno;Y. Tamura;Tao Wang;Y. Ao;B. Hatsukade;M. Kubo;K. Nakanishi;N. Hayatsu
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作者：
H. Umehata;I. Smail;A. M. Swinbank;K. Kohno;Y. Tamura;Tao Wang;Y. Ao;B. Hatsukade;M. Kubo;K. Nakanishi;N. Hayatsu
阿塔卡马大型毫米波阵列（ALMA）的深入调查发现了一群尘埃恒星形成的星系，它们在光学到近红外波长上是微弱的，甚至是未被探测到的。它们在短波长的模糊使得对种群的详细描述具有挑战性。在这里，我们提出了一个光谱红移识别和表征这些近红外暗星系之一由ALMA深查发现。探测到的[C i]（1-0）和CO（4-3）发射谱线确定了星系ADF22的精确红移。A2, z = 3.9913±0.0008。在多波长分析的基础上，ADF22。A2被发现是一个巨大的恒星形成星系，恒星质量M * = 1.1 +1.3−0.6 × 1011 M， SFR= 430+230−150 M yr−1。分子气体质量为M(H2) [CI] =（5.9±1.5）× 1010 M，气体分数约为35%，L[CI](1−0)/LIR和L[CI](1−0)/LCO（4−3）的比值反映了ADF22中星际介质的性质。A2与其他明亮的亚毫米星系是一致的。ADF22的性质。包括红移、恒星形成速率、恒星质量和耗尽时间尺度（τ deep≈0.1−0.2 Gyr）在内的A2也表明ADF22。A2具有z & 3处静止星系祖先的特征。我们的结果证明了ALMA连续映射和线扫描的力量，这有助于我们获得早期宇宙中星系形成的公正观点。
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 be z = 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 of M∗ = 1.1 +1.3 −0.6 × 1011 M and SFR= 430+230 −150 M yr−1 . The molecular gas mass was derived to be M(H2) [CI] = (5.9 ± 1.5) × 1010 M, indicating a gas fraction of ≈35%, and the ratios of L[CI](1−0)/LIR and L[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 at z & 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.