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arXiv 1209.0458astro-ph.CO
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隐藏的堡垒:复杂强透镜星系团SDSS J1029 +2623的结构和亚结构

The Hidden Fortress: Structure and substructure of the complex strong lensing cluster SDSS J1029+2623

Masamune Oguri, Tim Schrabback, Eric Jullo, Naomi Ota, Christopher S. Kochanek, Xinyu Dai, Eran O. Ofek, Gordon T. Richards, Roger D. Blandford, Emilio E. Falco, Janine Fohlmeister

摘要:

我们介绍了哈勃太空望远镜(HST)ACS和WFC 3对SDSS J1029+2623的观测,SDSS J1029+2623是一个由z=0.584的前景星系团产生的三图像类星体透镜系统。我们的强透镜分析揭示了另外6个多重成像星系。我们证实了复杂的性质的透镜集群的质量分布,与双峰分布偏离钱德拉X射线SB分布。对于红移z=2.197的类星体,爱因斯坦半径估计为θ_E=15.2”\pm 0.5”。结合强透镜效应、HST/ACS弱透镜效应和Subaru/Suprime-cam弱透镜效应的分析结果,我们得出了径向质量分布,发现最佳拟合维里质量为M_vir=(1.5+0.40-0.35)\times 10^14 h^-1 M_sun,浓度参数为c_vir=25.7+14.1-7.5。外半径处的透镜质量估计值比X射线质量估计值小约2倍。我们归因于这个大的质量差异,以冲击加热的团内气体在合并过程中,这也是建议的复杂的质量和气体分布和浓度参数的高值。在HST图像中,我们还发现了一个可能的星系GX,位于最暗的类星体图像C附近。包含GX解释了类星体图像之间的异常通量比。高度拉长的类星体宿主星系的形态也得到了很好的再现。最佳拟合模型表明类星体的总放大率为30,类星体宿主星系为35,并且具有与测量值一致的AB时间延迟。(节录)

英文摘要:

We present Hubble Space Telescope (HST) ACS and WFC3 observations of SDSS J1029+2623, a three-image quasar lens system produced by a foreground cluster at z=0.584. Our strong lensing analysis reveals 6 additional multiply imaged galaxies. We confirm the complex nature of the mass distribution of the lensing cluster, with a bimodal distribution which deviates from the Chandra X-ray SB distribution. The Einstein radius is estimated to be θ_E=15.2" \pm 0.5" for the quasar redshift of z=2.197. We derive a radial mass distribution from the combination of strong lensing, HST/ACS weak lensing, and Subaru/Suprime-cam weak lensing analysis results, finding a best-fit virial mass of M_vir=(1.5+0.40-0.35) \times 10^14 h^-1 M_sun and a concentration parameter of c_vir=25.7+14.1-7.5. The lensing mass estimate at the outer radius is smaller than the X-ray mass estimate by a factor of ~2. We ascribe this large mass discrepancy to shock heating of the intracluster gas during a merger, which is also suggested by the complex mass and gas distributions and the high value of the concentration parameter. In the HST image, we also identify a probable galaxy, GX, in the vicinity of the faintest quasar image C. The inclusion of GX explains the anomalous flux ratios between the quasar images. The morphology of the highly elongated quasar host galaxy is also well reproduced. The best-fit model suggests large total magnifications of 30 for the quasar and 35 for the quasar host galaxy, and has an AB time delay consistent with the measured value. (Abridged)

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