Two new large-separation gravitational lenses from SDSS
Two new large-separation gravitational lenses from SDSS
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DOI：
10.1111/j.1365-2966.2008.14075.x
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发表时间：
2008-06
影响因子：
4.8
通讯作者：
V. Belokurov;N. Evans;P. Hewett;A. Moiseev;R. McMahon;S. Sánchez;L. J. K. Ioa;Cambridge;
中科院分区：
文献类型：
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作者：
V. Belokurov;N. Evans;P. Hewett;A. Moiseev;R. McMahon;S. Sánchez;L. J. K. Ioa;Cambridge;
我们提供了两个大分离引力透镜的发现图像，以及后续的成像和光谱分析，这些图像是我们对宽弧的调查[剑桥·斯隆太空宽弧调查(Cassowary)]发现的。这项调查利用斯隆数字天空调查的多色测光技术，在红色星系周围发现了多个蓝色成分。Cassowary 2(或“柴郡猫”)是由两个质量较大的早期星系组成的，分别位于z=0.426和0.432，它们有两个背景源，第一个是z=0.97时的恒星形成星系，第二个是高红移星系(z>1.4)。至少有三张前一个来源的图像，可能有四个或更多后一个来源的图像，排列在两个巨大的弧线上。包围在半径∼11弧秒的较大圆弧内的质量为∼33 x 10 12 M⊙。气室3包括z=0.725源的三个明亮图像的弧形，由z=0.274处的前景椭圆透镜。圆弧的半径为∼4角秒，封闭质量为∼2.5x1012M⊙。再加上早期的发现，如宇宙马蹄形和8点钟弧形，这些新系统的分离介于典型的强星系透镜的角秒间隔透镜和弧分间隔星系团透镜之间，探测到星系质量函数的极高端。
We present discovery images, together with follow-up imaging and spectroscopy, of two large-separation gravitational lenses found by our survey for wide arcs [the CAmbridge Sloan Survey Of Wide ARcs in the skY (CASSOWARY)]. The survey exploits the multicolour photometry of the Sloan Digital Sky Survey to find multiple blue components around red galaxies. CASSOWARY 2 (or 'the Cheshire Cat') is composed of two massive early-type galaxies at z = 0.426 and 0.432, respectively, lensing two background sources, the first a star-forming galaxy at z = 0.97 and the second a high -redshift galaxy (z > 1.4). There are at least three images of the former source and probably four or more of the latter, arranged in two giant arcs. The mass enclosed within the larger arc of radius ∼11 arcsec is ∼33 x 10 12 M ⊙ . CASSOWARY 3 comprises an arc of three bright images of a z = 0.725 source, lensed by a foreground elliptical at z = 0.274. The radius of the arc is ∼4 arcsec and the enclosed mass is ∼2.5 x 10 12 M ⊙ . Together with earlier discoveries like the Cosmic Horseshoe and the 8 o'clock Arc, these new systems, with separations intermediate between the arcsecond-separation lenses of typical strong galaxy lensing and arcminute-separation cluster lenses, probe the very high end of the galaxy mass function.