Spectroscopic Confirmation of a Substantial Population of Luminous Red Galaxies at Redshifts z ≳ 2
Spectroscopic Confirmation of a Substantial Population of Luminous Red Galaxies at Redshifts z ≳ 2
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DOI：
10.1086/375156
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发表时间：
2003-03
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通讯作者：
P. V. van Dokkum;N. F. Förster Schreiber;M. Franx;E. Daddi;G. Illingworth;I. Labbé;A. Moorwood;H. Rix;H. Röttgering;G. Rudnick;A. van der Wel;P. P. van der Werf-P.;L. van Starkenburg
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作者：
P. V. van Dokkum;N. F. Förster Schreiber;M. Franx;E. Daddi;G. Illingworth;I. Labbé;A. Moorwood;H. Rix;H. Röttgering;G. Rudnick;A. van der Wel;P. P. van der Werf-P.;L. van Starkenburg
我们确认光谱的存在，在z 102的星系与休息帧光学颜色类似于正常的附近星系的人口。这些星系是通过红外光谱仪和甚大望远镜上的阵列照相机在前景星系团MS 1054-03周围获得的深空图像中的红色近红外颜色来识别的。用W. M.凯克望远镜。六个中的五个在2.43 ≤ z ≤ 3.52的范围内，这表明Js-Ks颜色选择非常有效。已确认的z > 2星系的静止坐标系紫外光谱显示出一系列的性质，其中两个星系显示出活动星系核的特征发射线，两个具有Lyα发射，一个只显示星际吸收线。它们的全光谱能量分布很好地描述了恒定的星星形成模型与年龄1.4-2.6 Gyr，除了一个星系的颜色表明一个尘埃星暴。已确认的z > 2星系非常明亮：它们的Ks星等在19.2-19.9之间，对应的静止坐标系绝对V星等在-24.8到-23.2之间。假设我们明亮的光谱样本代表了Js-Ks选定天体的总体，我们发现红色z = 2星系的表面密度为1.0000 arcmin-2至Ks = 21。面密度与KS为2的莱曼折选星系相当，它们可能演化为早型星系和球核。
We confirm spectroscopically the existence of a population of galaxies at z ≳ 2 with rest-frame optical colors similar to normal nearby galaxies. The galaxies were identified by their red near-infrared colors in deep images obtained with the Infrared Spectrometer and Array Camera on the Very Large Telescope of the field around the foreground cluster MS 1054-03. Redshifts of six galaxies with Js-Ks > 2.3 were measured from optical spectra obtained with the W. M. Keck telescope. Five out of six are in the range 2.43 ≤ z ≤ 3.52, demonstrating that the Js-Ks color selection is quite efficient. The rest-frame ultraviolet spectra of confirmed z > 2 galaxies display a range of properties, with two galaxies showing emission lines characteristic of active galactic nuclei, two having Lyα in emission, and one showing interstellar absorption lines only. Their full spectral energy distributions are well described by constant star formation models with ages 1.4-2.6 Gyr, except for one galaxy whose colors indicate a dusty starburst. The confirmed z > 2 galaxies are very luminous: their Ks magnitudes are in the range 19.2-19.9, corresponding to rest-frame absolute V magnitudes from -24.8 to -23.2. Assuming that our bright spectroscopic sample is representative for the general population of Js-Ks selected objects, we find that the surface density of red z ≳ 2 galaxies is ≈0.9 arcmin-2 to Ks = 21. The surface density is comparable to that of Lyman break-selected galaxies with Ks 2, and they could evolve into early-type galaxies and bulges.