论文标题
6DFGS和SDS的联合分析，用于宇宙结构的生长速度和重力测试
Joint analysis of 6dFGS and SDSS peculiar velocities for the growth rate of cosmic structure and tests of gravity
论文作者
论文摘要
通过将红移和距离指标组合来测量奇特速度是测量宇宙结构生长速率和在低红移时测试重力理论的有力方法。在这里，我们通过将观察到的基本平面奇异速度比较了6DF Galaxy调查（6DFGS）和Sloan Digital Sky Survey（SDSS）与预测的2M $ $ ++ $ redshift usevery的速度和密度。我们测量速度尺度参数$β\ equiv {ω_m^γ}/b = 0.372^{+0.034} _ { - 0.050} $和$ 0.314^{+0.031} _ { - 0.031} _ { - 0.047} $ for 6dfgs and Sdss $ yes $ yes $ ys $ iS $ g。增长指数和$ b $是标准化到星系的特征光度的偏差参数，$ l^*$。结合6DFGS和SDSS，我们获得$β= 0.341 \ pm0.024 $，这意味着在有效的redshift $ z = 0.035 $下，增长率和质量波动振幅的幅度为$Fσ_8= 0.338 = 0.338 \ pm0.027 $。采用$ω_m= 0.315 \ pm0.007 $，是Planck的青睐，并使用$γ= 6/11 $用于一般相对论，$γ= 11/16 $用于DGP重力，我们得到$ s_8（z = 0）=σ_8\ sqrt {ω_m/0.3} GR和DGP的$ 0.741 \ PM0.062 $。该测量值与其他大规模结构的其他低红移探针一致，但与最新的Planck CMB测量值相比，偏差超过$3σ$。我们的结果有利于增长指数$γ> 6/11 $或HUBBLE常数$ H_0> 70 $ \，km \，s $^{ - 1} $ \，mpc $^{ - 1} $或波动振幅$σ_8<0.8 <0.8 <0.8 <0.8 $或某些组合。迫在眉睫的红移调查，例如Taipan，Desi，wallaby和Ska1-Mid，将通过将宇宙结构的增长率测量到红移范围$ 0 <z <1 $来帮助解决这种张力。
Measurement of peculiar velocities by combining redshifts and distance indicators is a powerful way to measure the growth rate of cosmic structure and test theories of gravity at low redshift. Here we constrain the growth rate of structure by comparing observed Fundamental Plane peculiar velocities for 15894 galaxies from the 6dF Galaxy Survey (6dFGS) and Sloan Digital Sky Survey (SDSS) with predicted velocities and densities from the 2M$++$ redshift survey. We measure the velocity scale parameter $β\equiv {Ω_m^γ}/b = 0.372^{+0.034}_{-0.050}$ and $0.314^{+0.031}_{-0.047}$ for 6dFGS and SDSS respectively, where $Ω_m$ is the mass density parameter, $γ$ is the growth index, and $b$ is the bias parameter normalized to the characteristic luminosity of galaxies, $L^*$. Combining 6dFGS and SDSS we obtain $β= 0.341\pm0.024$, implying that the amplitude of the product of the growth rate and the mass fluctuation amplitude is $fσ_8 = 0.338\pm0.027$ at an effective redshift $z=0.035$. Adopting $Ω_m = 0.315\pm0.007$ as favoured by Planck and using $γ=6/11$ for General Relativity and $γ=11/16$ for DGP gravity, we get $S_8(z=0) = σ_8 \sqrt{Ω_m/0.3} =0.637 \pm 0.054$ and $0.741\pm0.062$ for GR and DGP respectively. This measurement agrees with other low-redshift probes of large scale structure but deviates by more than $3σ$ from the latest Planck CMB measurement. Our results favour values of the growth index $γ> 6/11$ or a Hubble constant $H_0 > 70$\,km\,s$^{-1}$\,Mpc$^{-1}$ or a fluctuation amplitude $σ_8 < 0.8$ or some combination of these. Imminent redshift surveys such as Taipan, DESI, WALLABY, and SKA1-MID will help to resolve this tension by measuring the growth rate of cosmic structure to 1\% in the redshift range $0 < z < 1$.
