Constraining the Volume Density of Dusty Star-forming Galaxies through the First 3 mm Number Counts from ALMA
Constraining the Volume Density of Dusty Star-forming Galaxies through the First 3 mm Number Counts from ALMA
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DOI：
10.3847/1538-4357/aaecd2
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
J. Zavala;C. Casey;E. D. Cunha;J. Spilker;J. Staguhn;J. Hodge;P. Drew
中科院分区：
文献类型：
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作者：
J. Zavala;C. Casey;E. D. Cunha;J. Spilker;J. Staguhn;J. Hodge;P. Drew
我们进行了盲搜索3毫米连续源使用阿尔马科学档案，以获得第一个星系数计数在这个波长。分析的数据来自对三个河外遗留领域的观测：COSMOS，CDF-S和UDS，包括超过130个单独的阿尔马带3点和一个有效的调查面积为200 arcmin 2的连续灵敏度，允许直接检测的无透镜尘埃恒星形成星系（DSFG）尘埃排放超出再电离时代。我们提出了一个目录的16个源检测在>5σ的通量密度，从数量计数。这些数量计数，然后使用放置约束DSFG的体积密度与经验向后演化模型。我们测量的3毫米数计数表明，DSFG的宇宙星星形成率密度在z = 4的贡献是不可忽略的。这与光学和近红外巡天观测所推断的被遮蔽星系在z > 4处的贡献急剧减少的普遍假设相反。这项工作证明了阿尔马-3毫米观测的力量，它可以达到杰出的连续灵敏度在典型的光谱线科学计划。对3毫米选定星系的进一步限制将是必不可少的，以完善星系形成和演化的模型，以及早期宇宙尘埃产生机制的模型。
We carry out a blind search of 3 mm continuum sources using the ALMA Science Archive to derive the first galaxy number counts at this wavelength. The analyzed data are drawn from observations toward three extragalactic legacy fields: COSMOS, CDF-S, and the UDS comprising more than 130 individual ALMA Band 3 pointings and an effective survey area of ≈200 arcmin2 with a continuum sensitivity that allows for the direct detection of unlensed Dusty Star-forming Galaxies (DSFGs) dust emission beyond the epoch of reionization. We present a catalog of 16 sources detected at >5σ with flux densities from which number counts are derived. These number counts are then used to place constraints on the volume density of DSFGs with an empirical backward evolution model. Our measured 3 mm number counts indicate that the contribution of DSFGs to the cosmic star formation rate density at z ≳ 4 is non-negligible. This is contrary to the generally adopted assumption of a sharply decreasing contribution of obscured galaxies at z > 4 as inferred by optical and near-infrared surveys. This work demonstrates the power of ALMA-3 mm observations, which can reach outstanding continuum sensitivities during typical spectral line science programs. Further constraints on 3 mm selected galaxies will be essential to refine models of galaxy formation and evolution as well as models of early universe dust production mechanisms.