arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0905.2967astro-ph.CO
收藏

进入下一代的特殊速度:来自SFI ++巡天的宇宙学参数

Peculiar velocities into the next generation: cosmological parameters from the SFI++ survey

Alexandra Abate, Pirin Erdogdu

摘要:

我们目前的宇宙学参数的限制,从SFI++星系特有的速度调查,最大的星系特有的速度样本。通过使用Abate等人(2008)开发的网格化方法进行分析。我们专注于受物质聚集影响的约束参数:sigma_8和生长指数gamma。假设一个一致性LCDM模型,我们发现σ_8 =0.91+0.22-0.18和伽玛=0.55+0.13-0.14后,边缘化的欧米茄_m。这些约束与来自使用不同方法的其他当前数据集的相同约束一致,并且具有类似的约束能力。最近,有几个索赔的奇特的速度测量不同意LCDM。相反,我们发现,尽管更高的σ_8值和更低的Ω_m值是优选的,但是当与WMAP 5相比时,这些值仍然是一致的。我们注意到,虽然我们的分析探测了各种尺度,但约束将由具有最小不确定性的较小尺度主导。这些结果表明,奇异速度分析是宇宙学的一个重要探索,对σ_8等参数提供了竞争性约束。它对生长函数导数的敏感性,特别是在红移为零的情况下,意味着它可以为结构形成的演化提供一个至关重要的低红移锚。利用具有不同系统学的不同探测器的重要性也是对最佳拟合宇宙学模型进行一致性检查的基本要求。

英文摘要:

We present cosmological parameter constraints from the SFI++ galaxy peculiar velocity survey, the largest galaxy peculiar velocity sample to date. The analysis is performed by using the gridding method developed in Abate et al. (2008). We concentrate on constraining parameters which are affected by the clustering of matter: sigma_8 and the growth index gamma. Assuming a concordance LCDM model we find sigma_8=0.91+0.22-0.18 and gamma=0.55+0.13-0.14 after marginalising over Omega_m. These constraints are consistent with, and have similar constraining power to, the same constraints from other current data sets which use different methods. Recently there have been several claims that the peculiar velocity measurements do not agree with LCDM. We find instead although a higher value of sigma_8 and a lower value of Omega_m are preferred, the values are still consistent when compared with WMAP5. We note that although our analysis probes a variety of scales, the constraints will be dominated by the smaller scales, which have the smallest uncertainties. These results show that peculiar velocity analysis is a vital probe of cosmology, providing competitive constraints on parameters such as sigma_8. Its sensitivity to the derivative of growth function, particularly down to redshift zero, means it can provide a vital low redshift anchor on the evolution of structure formation. The importance of utilising different probes with varying systematics is also an essential requirement for providing a consistency check on the best-fitting cosmological model.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑