The dynamics and structure of the cD galaxy in Abell 2029.
The dynamics and structure of the cD galaxy in Abell 2029.
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阿贝尔 2029 年 cD 星系的动力学和结构。
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
A. Dressler
中科院分区：
文献类型：
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作者：
A. Dressler
使用 Hale 5 m 和 SIT 数字摄谱仪获得了 A2029 中超过 100 kpc 的 cD 星系包层光谱。使用傅里叶互相关程序来测量 Ca II 和 G 带的 H 线和 K 线的位置、强度和宽度。从这些数据可以得出结论，星系不受旋转支持，并且线强度和隐含金属丰度在整个包络线中相对恒定。主要结果是速度色散随着星系半径的函数而增加，这与恒定 M/L 模型的预测相矛盾。粗略的维度论证表明，M/L/sub V/ 已从其核值约 12 上升到 Rapprox 处的约 67Msun/Lsun。 = 100 kpc。我们提出了一个详细的三分量各向同性 King 模型，该模型解释了 cD 星系的光度剖面和增加的速度色散，并提供了结合星团所需的质量。这三个组成部分被解释为（1）一个正常的椭圆星系（M/L/sub V/约=10），它通过其他星团成员的吸积获得了（2）一个发光材料晕（M/L/sub V/约=35），位于（3）一个黑暗（M/L/sub V/>500）星团填充和星团结合上层结构的中间。这种上层建筑可能是由曾经属于单个星团星系的物质组成的。确定 cD 星系是否与丰富星团的动力中心唯一相关的必要性将结合模型进行讨论。« 少
Spectra of the envelope of the cD galaxy in A2029 out to over 100 kpc have been obtained with the Hale 5 m and the SIT digital spectrograph. A Fourier cross-correlation program was used to measure the position, strength, and width of the H and K lines of Ca II and the G band. From these data it is concluded that the galaxy is not supported by rotation and that the line strength and implied metal abundance are relatively constant throughout the envelope.The primary result is that the velocity dispersion is increasing as a function of radius in the galaxy, in contradiction with the prediction of constant M/L models. A rough dimensional argument suggests that M/L/sub V/ has risen from its nuclear value of approx.12 to approx.67Msun/Lsun at Rapprox. = 100 kpc.We present a detailed three-component isotropic King model which accounts for the luminosity profile of the cD galaxy and the increasing velocity dispersion, and provides the mass necessary to bind the cluster. The three components are interpreted as (1) a normal elliptical galaxy (M/L/sub V/approx. =10) which has acquired (2) a halo of luminous material (M/L/sub V/approx. =35) through the accretion of other cluster members, positioned in the middlemore » of (3) a dark (M/L/sub V/>500) cluster-filling and cluster-binding superstructure. This superstructure may be composed of material which at one time belonged to individual cluster galaxies.The necessity of determining whether cD galaxies are uniquely associated with the dynamical centers of rich clusters is discussed in connection with the model.« less