Biased Cold Dark Matter Theory: Trouble from Rich Clusters?
Biased Cold Dark Matter Theory: Trouble from Rich Clusters?
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DOI：
10.1086/185460
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发表时间：
1989-06
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影响因子：
--
通讯作者：
A. Evrard
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文献类型：
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作者：
A. Evrard
在冷暗物质（CDM）占主导地位的宇宙中，丰富的集群的预期人口是非常敏感的光谱归一化，其逆定义的偏置参数B。最近对三个红移z约为0.5的高速色散星系团的观测表明，该理论的B值低得惊人。如果从表面上看，观察结果意味着一个无偏模型，B约为1。然而，这个B值预测的低红移星系团数量大约是观测到的10倍。低红移数据支持B在1.5-1.9范围内的值。据认为，穷人的统计和恢复的内禀速度色散从红移测量的不确定性排除了可靠的测定B目前。对星系团X射线温度进行调查，完成中等红移，将证明在决定这个问题上是非常宝贵的。参考文献21篇。
The expected population of rich clusters in a cold dark matter (CDM)-dominated universe is extremely sensitive to the spectrum normalization, the inverse of which defines the bias parameter b. Recent observations of three high-velocity dispersion clusters at redshifts z roughly 0.5 indicate an alarmingly low value of b for the theory. If taken at face value, the observations imply an unbiased model, b about 1. However, this value of b predicts roughly 10 times as many low-redshift clusters as are observed. The low-redshift data favor values in the range b about 1.5-1.9. It is argued that poor statistics and the uncertainty in recovering intrinsic velocity dispersions from redshift measurements preclude a reliable determination of b at present. A survey of cluster X-ray temperatures complete to moderate redshifts would prove invaluable in deciding this issue. 21 refs.