Measuring the cosmological constant with redshift surveys
Measuring the cosmological constant with redshift surveys
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DOI：
10.1093/mnras/282.3.877
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发表时间：
1996-05
影响因子：
4.8
通讯作者：
W. Ballinger;J. Peacock;A. Heavens
中科院分区：
文献类型：
--
作者：
W. Ballinger;J. Peacock;A. Heavens
有人提出，宇宙学常数$\Lambda$可以从大尺度结构的几何效应来测量。一个积极的真空密度导致相关函数的轮廓被压扁在径向方向上计算时，假设一个物质占主导地位的模型。我们表明，这种影响将有点难以检测比以前的计算表明：挤压因子可能是$<1.3$，考虑到现实的限制，对$\欧米茄$的物质贡献。此外，几何畸变有可能与星系团增长所伴随的特殊速度所引起的红移空间畸变相混淆。这些依赖于密度和偏置参数通过组合$\beta\equiv \Omega~{0.6}/B$，我们表明，几何扁平因子$F$的主要实际效果是模拟引力不稳定性与$\beta_{\rm eff}\simeq 0.5（F-1）$。尽管如此，有足够大的数据集，有可能区分这两种效应;我们详细讨论了如何做到这一点。新一代星系和类星体的红移巡天有可能探测到非零真空密度，如果它存在于宇宙学上感兴趣的水平。
It has been proposed that the cosmological constant $\Lambda$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction when calculated assuming a matter-dominated model. We show that this effect will be somewhat harder to detect than previous calculations have suggested: the squashing factor is likely to be $<1.3$, given realistic constraints on the matter contribution to $\Omega$. Moreover, the geometrical distortion risks being confused with the redshift-space distortions caused by the peculiar velocities associated with the growth of galaxy clustering. These depend on the density and bias parameters via the combination $\beta\equiv \Omega~{0.6}/b$, and we show that the main practical effect of a geometrical flattening factor $F$ is to simulate gravitational instability with $\beta_{\rm eff}\simeq 0.5(F-1)$. Nevertheless, with datasets of sufficient size it is possible to distinguish the two effects; we discuss in detail how this should be done. New-generation redshift surveys of galaxies and quasars are potentially capable of detecting a non-zero vacuum density, if it exists at a cosmologically interesting level.