标题： 微弱亚毫米星系族群的红移分布 显示英文标题

标题： Redshift Distribution of the Faint Submillimeter Galaxy Population

摘要： 我们展示了凯克II号望远镜上的LRIS光谱后续研究，对象是可能的光学对应体，这些对应体选自由JCMT上的SCUBA探测仪阵列完成的850微米对大质量引力透镜团的巡天中选出的星系样本。 这些源代表了一群明亮的尘埃星系，它们负责了由COBE探测到的850微米背景辐射的主要部分，因此也负责了宇宙总红外辐射的相当一部分。 我们为20个星系提供了可靠的红移数据，并为另外4个从14个亚毫米源误差框中选出的星系提供了红移上限。样本中的两个其他亚毫米检测没有明显的光学对应体，而最后一个亚毫米源只能在我们的光谱观测完成后通过成像数据确认。 通过对4个亚毫米源的光学识别已经得到了确认，要么是通过毫米波段的CO检测（两组z=2.55和z=2.80的星系），要么是通过它们的光谱能量分布特性（引力透镜团中的两个中央cD星系）。 基于对应体的光学光谱性质（星爆或活动星系核特征）的合理论据允许我们将另外两个可能的对应体识别为z=1.06和1.16。 对于剩下的8个案例，通常不清楚所识别出的光学源中哪个，如果有的话，是真正的对应体。 这些源的可能对应体的红移范围从z=0.18到z=2.11。 根据当前的识别，我们认为亚毫米波段的绝大部分星系际背景光是由z<3的源发射的，因此高度隐藏源（无论是活动星系核还是星爆）的峰值活动位于相对较低的红移处。 （摘要） 显示英文摘要

摘要： We present a Keck II LRIS spectroscopic follow-up study of the possible optical counterparts to a flux-limited sample of galaxies selected from an 850-micron survey of massive lensing clusters using the SCUBA bolometer array on the JCMT. These sources represent a population of luminous dusty galaxies responsible for the bulk of the 850-micron background detected by COBE and thus for a substantial fraction of the total far-infrared emission in the Universe. We present reliable redshifts for 20 galaxies and redshift limits for a further 4 galaxies selected from the error-boxes of 14 submm sources. Two other submm detections in the sample have no obvious optical counterparts, and the final submm source was only identified from imaging data after the completion of our spectroscopic observations. The optical identifications for 4 of the submm sources have been confirmed through either their detection in CO at mm-wavelengths (two pairs of galaxies at z=2.55 and z=2.80) or from the characteristics of their spectral energy distributions (two of the central cD galaxies in the lensing clusters). Plausible arguments based on the optical spectral properties (starburst or AGN signatures) of the counterparts allow us to identify a further two likely counterparts at z=1.06 and 1.16. For the remaining 8 cases, it is not always clear which, if any, of the optical sources identified are the true counterparts. Possible counterparts for these have redshifts ranging from z=0.18 to z=2.11. Working with the current identifications, we suggest that the majority of the extragalactic background light in the submm is emitted by sources at z<3 and hence that the peak activity in highly-obscured sources (both AGN and starbursts) lies at relatively modest redshifts. (Abridged)