The Canada-UK Deep Submillimeter Survey. IV. The Survey of the 14 Hour Field
The Canada-UK Deep Submillimeter Survey. IV. The Survey of the 14 Hour Field
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加拿大-英国深亚毫米波调查。
DOI：
10.1086/316823
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Yun
中科院分区：
文献类型：
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作者：
S. Eales;S. Lilly;T. Webb;L. Dunne;W. Gear;D. Clements;M. Yun
我们使用Scuba调查了≃50 arcmin 2的区域，探测到19个源，其灵敏度下限为3σ，在850μm处。蒙特卡罗模拟表明，在这次和类似的Scuba调查中，由于源混淆和噪声的影响，源的通量向上倾斜，导致Scuba已经解决的850μm背景的一部分被高估了1.4倍。一旦对这种效果进行了校正，大约20%的背景就解决了。这些模拟也被用来量化混乱对震源位置的影响。在19个Scuba源中，5个是微型射电源，2个是国际标准化组织15μm源。射电/亚毫米级流量比表明，这些星系中的尘埃是由年轻恒星加热的，而不是活动的星系核。平均450μm/850μm通量比的上限意味着潜水星系的z2，或者，如果它们的红移较低，尘埃通常比ULIRG中的尘埃更冷。我们使用简单的演化模型来解决关于Scuba源的主要问题：(1)高红移时恒星形成的多大部分被尘埃掩盖？(2)亚毫米光度密度在某些红移时达到最大值吗？(3)如果Scuba源是原椭圆形的，椭圆到底是什么时候形成的？然而，我们表明，观察结果还不足以回答这些问题。例如，有一些可以接受的模型，其中尘埃隐藏的高红移恒星形成的数量是光学波长下的10倍，但也有一些可以接受的模型，其中隐藏的恒星形成的数量比光学上看到的要少。有一些可以接受的模型，其中在红移3之前几乎没有恒星形成(正如分级星系形成模型中可能预期的那样)，但也有一些模型中有30%的恒星是通过这种红移形成的。回答这些问题的关键是测量尘埃温度和水肺来源的红移。
We have used SCUBA to survey an area of ≃ 50 arcmin2, detecting 19 sources down to a 3 σ sensitivity limit of ∼3.5 mJy at 850 μm. Monte Carlo simulations have shown that the fluxes of sources in this and similar SCUBA surveys are biased upward by the effects of source confusion and noise, leading to an overestimate by a factor of ∼1.4 in the fraction of the 850 μm background that has been resolved by SCUBA. Once a correction is made for this effect, about 20% of the background has been resolved. The simulations have also been used to quantify the effects of confusion on source positions. Of the 19 SCUBA sources, five are microjansky radio sources, and two are ISO 15 μm sources. The radio/submillmeter flux ratios imply that the dust in these galaxies is being heated by young stars rather than active galactic nuclei. The upper limit to the average 450 μm/850 μm flux ratio implies either that the SCUBA galaxies are at z 2 or, if they are at lower redshifts, that the dust is generally colder than in ULIRGs. We have used simple evolution models to address the major questions about the SCUBA sources: (1) What fraction of the star formation at high redshift is hidden by dust? (2) Does the submillimeter luminosity density reach a maximum at some redshift? (3) If the SCUBA sources are protoellipticals, when exactly did ellipticals form? We show, however, that the observations are not yet good enough to answer these questions. There are, for example, acceptable models in which 10 times as much high-redshift star formation is hidden by dust as is seen at optical wavelengths, but also acceptable ones in which the amount of hidden star formation is less than that seen optically. There are acceptable models in which very little star formation occurred before a redshift of 3 (as might be expected in models of hierarchical galaxy formation), but also ones in which 30% of the stars have formed by this redshift. The key to answering these questions are measurements of the dust temperatures and redshifts of the SCUBA sources.