Galaxy Halo Masses from Galaxy-Galaxy Lensing
Galaxy Halo Masses from Galaxy-Galaxy Lensing
复制标题
星系-星系透镜的星系晕质量
DOI：
10.1086/321441
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
L. Cowie
中科院分区：
文献类型：
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作者：
G. Wilson;N. Kaiser;G. Luppino;L. Cowie
我们给出了用UH8K CCD马赛克相机对加拿大-法国-夏威夷望远镜拍摄的图像进行星系透镜分析所获得的红移为0.1<；z<；0.9的明亮早期类型星系的扩展暗晕轮廓的测量结果。在I和V中观测了6个0.5°5×0.5°5场，每个场总共持续2小时，从而得到每个场包含约20,000个星系的星表。我们使用V-I颜色和I星等选择明亮的早期类型星系作为透镜星系，产生了一个具有相当确定的红移和绝对星等M~M*±1的大质量透镜样本。我们将这些透镜与角距离为20‘’<；θ<；60‘’的弱星系配对，对应的物理半径为26<；r<；77h-1kpc(z=0.1)和105h-1kpc(z=0.9)，并计算了这些暗星系的平均切向切变γT(θ)。对于平坦的旋转曲线光晕，切变的半径大约为γT∝1/θ。剪切值与透镜星系光度的平方根成正比。如果给定半径的晕质量按M∝变化，就像小半径的情况一样，这是最优的，在这种情况下，我们的结果给出了平坦的波长(ΩM0=0.3，Ωλ0=0.7)宇宙学(爱因斯坦-德西特的v*=269公里S-1)宇宙学(v*=269公里S-1)宇宙学(爱因斯坦-德西特的)，在v*=238 km S-1的r~50-200h-1kpc的星晕的平均自转速度的值，几乎没有证据表明演化具有红移。这些晕质量比从小尺度动力学测量中推算的简单的完全平坦的旋转曲线要低一些(2-3倍)。它们也比从研究最充分的X射线晕中发现的晕质量要低得多。然而，在Lambda-CDM模拟中，它们确实与相同丰度的光晕质量非常吻合。我们发现M/LB晕的质量光比为12 1±2 8h(r/10 0h-1kpc)(对于L星系)，这些晕构成了闭合密度的Ω≃0.0 4±0.0 1(r/10 0h-1kpc)。
We present measurements of the extended dark halo profiles of bright early-type galaxies at redshifts 0.1 < z < 0.9 obtained via galaxy-galaxy lensing analysis of images taken at the Canada-France-Hawaii Telescope using the UH8K CCD mosaic camera. Six 0.°5 × 0.°5 fields were observed for a total of 2 hr each in I and V, resulting in catalogs containing ~20,000 galaxies per field. We used V-I color and I magnitude to select bright early-type galaxies as the lens galaxies, yielding a sample of massive lenses with fairly well-determined redshifts and absolute magnitudes M ~ M* ± 1. We paired these with faint galaxies lying at angular distances 20′′ < θ < 60′′, corresponding to physical radii of 26 < r < 77 h-1 kpc (z = 0.1) and 105 < r < 315 h-1 kpc (z = 0.9), and computed the mean tangential shear γT(θ) of the faint galaxies. The shear falls off with radius roughly as γT ∝ 1/θ as expected for flat rotation curve halos. The shear values were weighted in proportion to the square root of the luminosity of the lens galaxy. This is optimal if the halo mass at a given radius varies as M ∝ , as is the case at smaller radii, and in this context our results give a value for the average mean rotation velocity of an L* galaxy halo at r ~ 50-200 h-1 kpc of v* = 238 km s-1 for a flat lambda (Ωm0 = 0.3,Ωλ0 = 0.7) cosmology (v* = 269 km s-1 for Einstein-de Sitter) and with little evidence for evolution with redshift. These halo masses are somewhat (2-3 times) lower than a simple perfectly flat rotation curve extrapolation from smaller scale dynamical measurements. They are also considerably lower than the masses of halos found from the best-studied X-ray halos. They do, however, agree extremely well with the masses of halos of the same abundance in lambda-CDM simulations. We find a mass-to-light ratio of M/LB ≃ 121 ± 28h(r/100 h-1 kpc) (for L* galaxies) and these halos constitute Ω ≃ 0.04 ± 0.01(r/100 h-1 kpc) of closure density.