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arXiv 1504.02100astro-ph.CO
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用Sloan数字巡天III重子振荡光谱巡天星系的增长率测量检验广义相对论

Testing General Relativity with Growth rate measurement from Sloan Digital Sky Survey III Baryon Oscillations Spectroscopic Survey galaxies

Shadab Alam, Shirley Ho, Mariana Vargas-Magaña, Donald P. Schneider

摘要:

天文物体的测量红移($z$)是哈勃衰退、引力红移和特有速度的组合。由红移推断的星系视距受星系红移中特有的速度分量的影响,这在相关函数中被观察为各向异性。这种各向异性使我们能够测量物质的线性增长率($fσ_8$)。我们利用斯隆数字巡天III(SDSS III)重子振荡光谱巡天(BOSS)的CMASS样品在$z=0.57$测量了$fσ_8$。星系样本由690,826个大质量星系组成,红移范围为0.43-0.7,覆盖8498 deg $^2$。本文报道了利用卷积拉格朗日微扰理论(CLPT)和高斯流模型(GSRSD)对$fσ_8$和背景宇宙学参数的首次同时测量。当我们在所有其他宇宙学参数上边缘化的同时包括普朗克CMB似然时,我们在有效红移($\bar{z}=0.57$)处得到了$fσ_8=0.462\pm0.041$(9\%精度)的约束。我们还测量了$bσ_8=1.19\pm0.03$、$H(z=0.57)=89.2\pm3.6$ km s、$^{-1}$ Mpc、$^{-1}$和$D_A(z=0.57)=1401\pm23$ Mpc。我们的分析也提高了3倍的普朗克相比,只有测量($Ω_c h^2=0.1196 \pm 0.0031$)的约束$Ω_c h^2=0.1196\pm0.0009$。我们的结果与普朗克$Λ$ CDM-GR预测和所有其他CMASS测量结果一致,尽管我们的理论模型相当不同。这种一致性表明,在多个红移处从红移空间扭曲测量$fσ_8$将是对引力理论的敏感探测,这在很大程度上是模型独立的,使我们能够对引力的替代模型施加模型独立的约束。

英文摘要:

The measured redshift ($z$) of an astronomical object is a combination of Hubble recession, gravitational redshift and peculiar velocity. The line of sight distance to a galaxy inferred from redshift is affected by the peculiar velocity component of galaxy redshift, which is observed as an anisotropy in the correlation function. This anisotropy allows us to measure the linear growth rate of matter ($fσ_8$). We measure the $fσ_8$ at $z=0.57$ using the CMASS sample from Data Release 11 of Sloan Digital Sky Survey III (SDSS III) Baryon Oscillations Spectroscopic Survey (BOSS). The galaxy sample consists of 690,826 massive galaxies in the redshift range 0.43-0.7 covering 8498 deg$^2$. Here we report the first simultaneous measurement of $fσ_8$ and background cosmological parameters using Convolution Lagrangian Perturbation Theory (CLPT) with Gaussian streaming model (GSRSD). We arrive at a constraint of $fσ_8=0.462\pm0.041$ (9\% accuracy) at effective redshift ($\bar{z}=0.57$) when we include Planck CMB likelihood while marginalizing over all other cosmological parameters. We also measure $bσ_8=1.19\pm0.03$, $H(z=0.57)=89.2\pm3.6$ km s$^{-1}$ Mpc$^{-1}$ and $D_A(z=0.57)=1401\pm23$ Mpc. Our analysis also improves the constraint on $Ω_c h^2=0.1196\pm0.0009$ by a factor of 3 when compared to the Planck only measurement($Ω_c h^2=0.1196 \pm 0.0031$). Our results are consistent with Planck $Λ$CDM-GR prediction and all other CMASS measurements, even though our theoretical models are fairly different. This consistency suggests that measurement of $fσ_8$ from Redshift space distortions at multiple redshifts will be a sensitive probe of the theory of gravity that is largely model independent, allowing us to place model-independent constraints on alternative models of gravity.

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。

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