The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: The Nature of the Faintest Dusty Star-forming Galaxies
The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: The Nature of the Faintest Dusty Star-forming Galaxies
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DOI：
10.3847/1538-4357/ab99a2
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发表时间：
2020-06
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通讯作者：
M. Aravena;L. Boogaard;J. G'onzalez-L'opez;R. Decarli;F. Walter;C. Carilli;I. Smail;A. Weiss;R. Assef;F. Bauer;R. Bouwens;P. Cortés;P. Cox;E. da Cunha;E. Daddi;T. Díaz-Santos;H. Inami;R. Ivison;M. Novak;G. Popping;D. Riechers;P. P. van der Werf-P.;J. Wagg
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作者：
M. Aravena;L. Boogaard;J. G'onzalez-L'opez;R. Decarli;F. Walter;C. Carilli;I. Smail;A. Weiss;R. Assef;F. Bauer;R. Bouwens;P. Cortés;P. Cox;E. da Cunha;E. Daddi;T. Díaz-Santos;H. Inami;R. Ivison;M. Novak;G. Popping;D. Riechers;P. P. van der Werf-P.;J. Wagg
我们提出了一个表征的物理性质的样本35安全检测，尘埃星系在深阿尔马1.2毫米的图像作为阿尔马光谱调查的哈勃超深场（ASPECS）大计划的一部分。该样本由通过光学/红外源位置先验识别的26个额外源补充。利用它们良好表征的光谱能量分布，我们得到了恒星质量中值和星星形成率（SFR）分别为和30 M/年，四分位距分别为（2.4-11.7）× 1010 M/年和20-50 M/年。我们得出一个中位数光谱红移为1.8，四分位数范围1.1-2.6，显着低于在较浅的，宽视场的调查中检测到的亚毫米星系。我们发现，59% ± 13%，6% ± 4%和34% ± 9%的源分别在SFR-恒星质量关系或主序列（MS）的±0.4 dex之内，之上和之下。ASPECS星系密切遵循SFR-分子气体质量关系和其他先前建立的标度关系，确认了气体-恒星质量比从z = 0.5增加到2.5的五倍，以及气体耗尽时间尺度的温和演变，在z = 1-3时的典型值为0.7 Gyr。ASPECS星系明显位于MS下方，这是一个利用率很低的参数空间，气体与恒星的质量比很低，为0.1-0.2，耗尽时间尺度很长，>1 Gyr。星系沿着MS在所有的红移上控制着分子气体的宇宙密度。MS以上的星系在z < 1到z = 2.5的范围内对总气体储量的贡献逐渐增加，而MS以下的星系则相反。
We present a characterization of the physical properties of a sample of 35 securely detected, dusty galaxies in the deep ALMA 1.2 mm image obtained as part of the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS) Large Program. This sample is complemented by 26 additional sources identified via an optical/infrared source positional prior. Using their well-characterized spectral energy distributions, we derive median stellar masses and star formation rates (SFR) of and 30 M☉ yr−1, respectively, and interquartile ranges of (2.4–11.7) × 1010 M☉ and 20–50 M☉ yr−1. We derive a median spectroscopic redshift of 1.8 with an interquartile range 1.1–2.6, significantly lower than submillimeter galaxies detected in shallower, wide-field surveys. We find that 59% ± 13%, 6% ± 4%, and 34% ± 9% of our sources are within, above, and below±0.4 dex from the SFR–stellar-mass relation or main sequence (MS), respectively. The ASPECS galaxies closely follow the SFR–molecular gas mass relation and other previously established scaling relations, confirming a factor of five increase of the gas-to-stellar-mass ratio from z = 0.5 to 2.5 and a mild evolution of the gas depletion timescales with a typical value of 0.7 Gyr at z = 1–3. ASPECS galaxies located significantly below the MS, a poorly exploited parameter space, have low gas-to-stellar-mass ratios of ∼0.1–0.2 and long depletion timescales >1 Gyr. Galaxies along the MS dominate the cosmic density of molecular gas at all redshifts. Systems above the MS have an increasing contribution to the total gas reservoirs from z < 1 to z = 2.5, while the opposite is found for galaxies below the MS.