PRIMUS: OBSCURED STAR FORMATION ON THE RED SEQUENCE
PRIMUS: OBSCURED STAR FORMATION ON THE RED SEQUENCE
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普利莫斯：红色序列上模糊的恒星形成
DOI：
10.1088/0004-637x/726/2/110
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Aird
中科院分区：
文献类型：
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作者：
G. Zhu;M. Blanton;S. Burles;A. Coil;R. Cool;D. Eisenstein;J. Moustakas;Kenneth C. Wong;J. Aird
我们量化了中等红移（0.1 < z < 0.5）的星系的比例，这些星系在光学上看起来是红的和死的，但实际上包含在红外（IR）中可探测到的模糊恒星形成，使用PRIsm多目标巡天（PRIMUS）。PRIMUS已经在9.1°2的天空中测量了~ 120,000个强大的红移，精度为σz/(1 + z) ~ 0.5%，深度为i ~ 23 (AB)，红移为z ~ 1。我们利用斯皮策太空望远镜从SWIRE和S-COSMOS调查中获得的现有深红外成像，专门瞄准了6.7度的区域。我们在这些场中选择了3310个0.1 < z < 0.5的红序星系的i波段通量限制样本（在SWIRE场中i < 20等，在S-COSMOS场中i < 21等），我们可以用红外颜色可靠地区分模糊恒星形成（SF）和静止星系。我们的样本构成了研究红色序列上被遮挡恒星形成的最大的中间红移星系样本，并且我们首次对被遮挡的SF星系的比例作为光度函数进行了定量分析。我们发现，平均而言，在L ~ L*，大约15%的红序星系具有与SF星系一致的红外颜色。被遮挡的SF星系的百分比每等增加约8%，亮度从最高亮度降低到L ~ 0.2 L*。我们的结果表明，很大一部分红序星系正在形成恒星，因此基于光学颜色的星系演化研究需要考虑到这种复杂性。
We quantify the fraction of galaxies at moderate redshifts (0.1 < z < 0.5) that appear red-and-dead in the optical, but in fact contain obscured star formation detectable in the infrared (IR), with the PRIsm MUlti-object Survey (PRIMUS). PRIMUS has measured ∼120,000 robust redshifts with a precision of σz/(1 + z) ∼ 0.5% over 9.1 deg2 of the sky to the depth of i ∼ 23 (AB), up to redshift z ∼ 1. We specifically targeted 6.7 deg2 fields with existing deep IR imaging from the Spitzer Space Telescope from the SWIRE and S-COSMOS surveys. We select in these fields an i-band flux-limited sample (i < 20 mag in the SWIRE fields and i < 21 mag in the S-COSMOS field) of 3310 red-sequence galaxies at 0.1 < z < 0.5 for which we can reliably classify obscured star-forming (SF) and quiescent galaxies using IR color. Our sample constitutes the largest galaxy sample at intermediate redshift to study obscured star formation on the red sequence, and we present the first quantitative analysis of the fraction of obscured SF galaxies as a function of luminosity. We find that on average, at L ∼ L*, about 15% of red-sequence galaxies have IR colors consistent with SF galaxies. The percentage of obscured SF galaxies increases by ∼8% per mag with decreasing luminosity from the highest luminosities to L ∼ 0.2 L*. Our results suggest that a significant fraction of red-sequence galaxies have ongoing star formation and that galaxy evolution studies based on optical color therefore need to account for this complication.