爱因斯坦环及其星系团环境  

Gravitational Rings and Their Cluster Environment

作　　者：涂泓[1] 朱炯明[1] 束成钢[1,2] 

机构地区：[1]上海师范大学数理信息学院,上海200234 [2]中国科学院上海天文台,上海200030

出　　处：《天文学进展》2009年第3期220-228,共9页Progress In Astronomy

基　　金：国家自然科学基金资助项目(10333020;10528307;10778725);973计划(2007CB815402);上海市科委项目资助基金(07 dz 22020;DZL 805;08240514100);上海师范大学一般项目(DKL 932)

摘　　要：该文研究了以星系作为透镜体产生的切向弧(即"爱因斯坦环")的强引力透镜现象,并对该领域近年来的观测和研究作了总结。对形成这些强引力透镜"环"的星系所进行的研究表明,其附近存在的质量所产生的会聚和剪切对透镜的质量分布模型非常敏感。在大视场巡天中找到的这种爱因斯坦环的数目相当多,大约是每平方度10个,其中"强引力透镜巡天"(Strong Lensing Legacy Survey,SL2S)提供了大量处于星系团视场中的由椭圆星系产生的爱因斯坦环样本。系统地研究星系团外围存在的爱因斯坦环,一方面可以理解星系团环境对爱因斯坦环的影响,另一方面可以利用它们来探测星系团的物质分布,并进而对冷暗物质宇宙学提供新的探测方法。Gravitational lensing, light from the background sources beaded by foreground massive objects predicted by the General Relativity, has been adopted as an efficient tool to study the mass distribution in the universe. ＂Rings＂ in the present paper are the results of galaxy-galaxy strong lensing, which have been found widely in individual surveys. It can be estimated theoretically that there should be about 10 gravitational rings observed per square degree in the current surveys. While isolated ＂rings＂ appearing in the field are relatively easy to study, they can be considered to constrain the slope of the density profiles of clusters if they appear in the cluster environment since the conditions of ＂rings＂ formation are sensitive to the external shear and convergence produced by nearby mass condensations. In the present paper, the current observational projects and the relative studies on ＂rings＂ are briefly introduced for both SLACS （Sloan Lens ACS） survey and SL2S （Strong leasing legacy surveay） in CFHTLS （Canada-France-Hawaii Telescope Legacy Survey）. The current conclusions from SLACS are as follows. （i） The slope of density profiles of the massive elliptical galaxies produced ＂rings＂ seems to be in consistence with the isothermal profile （with ραr^-2±13）; （ii） The distributions of both position angles and ellipticities of baryonic matter trace their host dark matter halo well （with position angle difference between light and total mass （△θ） = 0°4-3° degrees and ellipiticity ratio （qSIE/q＊）= 0.99）. The studies of ＂rings＂ occur in cluster environment are also summarized including simulations and the applications of ＂rings＂ to constrain the slope of mass profile of a clusters, and the conclusions are positive. Comparing to the ＂rings＂ in field, the ＂rings＂ in cluster environments show some special features. （i） As galaxies are crossing the higher density region of the cluster, the DM halo component is tidally stripped. （ii�

关 键 词：引力透镜 星系 星系团 爱因斯坦环 暗物质 

分 类 号：P157[天文地球—天文学] O412.1[理学—理论物理]