标题： 二维度场星系红移巡天的DWT功率谱 显示英文标题

标题： The DWT Power Spectrum of the two-degree Field Galaxy Redshift Survey

摘要： 二维场星系红移巡天（2dFGRS）样本的功率谱是用离散小波变换（DWT）方法估计的。 在$0.04 <k< 2.3 h$Mpc$^{-1}$范围内的DWT功率谱对于三个在连接绝对星等区间$-19 \sim -18$、$-20 \sim -19$和$-21 \sim -20$中定义的体积限制样本进行了测量。 我们表明，DWT功率谱可以有效区分$\Lambda$CDM模型的$\sigma_8=0.84$和$\sigma_8=0.74$。 我们采用最大似然方法，用偏置参数$b$、成对速度弥散$\sigma_{pv}$和红移畸变参数$\beta=\Omega_m^{0.6}/b$对测量的DWT功率谱进行三参数拟合。 拟合结果表明，在一个$\sigma_8=0.84$宇宙中，三个样本给出的最佳拟合$\Omega_m$在范围$0.28 \sim 0.36$内是一致的，三个样本的最佳拟合$\sigma_{pv}$分别为$398^{+35}_{-27}$，$475^{+37}_{-29}$和$550 \pm 20$km/s。 然而在$\sigma_8=0.74$模型中，我们的三个样本给出了非常不同的$\Omega_m$值。 我们通过使用红移畸变的经验公式重复了拟合。 低$\sigma_8$模型的结果仍然较差，特别是最佳值$\sigma_{pv}$中的一个高达$10^3$km/s。 2dFGRS 的功率谱似乎不利于密度涨落振幅较低的模型。 显示英文摘要

摘要： The power spectrum of the two-degree Field Galaxy Redshift Survey (2dFGRS) sample is estimated with the discrete wavelet transform (DWT) method. The DWT power spectra within $0.04 <k< 2.3 h$Mpc$^{-1}$ are measured for three volume-limited samples defined in connective absolute magnitude bins $-19 \sim -18$, $-20 \sim -19$ and $-21 \sim -20$. We show that the DWT power spectrum can effectively distinguish $\Lambda$CDM models of $\sigma_8=0.84$ and $\sigma_8=0.74$. We adopt maximum likelihood method to perform three-parameter fitting with bias parameter $b$, pairwise velocity dispersion $\sigma_{pv}$ and redshift distortion parameter $\beta=\Omega_m^{0.6}/b$ to the measured DWT power spectrum. Fitting results denotes that in a $\sigma_8=0.84$ universe the best fitted $\Omega_m$ given by the three samples are consistent in the range $0.28 \sim 0.36$, and the best fitted $\sigma_{pv}$ are $398^{+35}_{-27}$, $475^{+37}_{-29}$ and $550 \pm 20$km/s for the three samples, respectively. However in the model of $\sigma_8=0.74$, our three samples give very different values of $\Omega_m$. We repeat the fitting by using empirical formula of redshift distortion. The result of the model of low $\sigma_8$ is still poor, especially, one of the best value $\sigma_{pv}$ is as large as $10^3$km/s. The power spectrum of 2dFGRS seems in disfavor of models with low amplitude of density fluctuations.