Toward a Precise Measurement of Matter Clustering: Lyα Forest Data at Redshifts 2-4
Toward a Precise Measurement of Matter Clustering: Lyα Forest Data at Redshifts 2-4
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实现物质聚类的精确测量：红移 2-4 处的 Lyα 森林数据
DOI：
10.1086/344099
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
D. Tytler
中科院分区：
文献类型：
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作者：
R. Croft;D. Weinberg;M. Bolte;S. Burles;L. Hernquist;N. Katz;D. Kirkman;D. Tytler
我们测量了 Lyα 森林光谱大样本中的填充因子、相关函数和透射通量的功率谱，其中包含 30 个 Keck HIRES 光谱和 23 个 Keck LRIS 光谱。我们使用 Croft 等人方法的改进版本，从通量功率谱 PF(k) 推断线性物质功率谱 P(k)。这解释了红移空间畸变、非线性和热展宽对 PF(k) 形状的影响。 P(k)在样本红移范围内（z ≈ 2-4）的形状和幅度的演变与重力不稳定的预测一致，这意味着非重力涨落对Lyα森林的结构没有太大贡献。我们对 P(k) 的基准测量来自数据的子集，其值为 2.3 < z < 2.9，平均吸收红移 ⟨z⟩ = 2.72，总路径长度 Δz ≈ 25。它在波数 kp = 0.03 (km s-1)-1 处具有无量纲振幅 Δ2(kp) = 0.74，并且可以通过指数 ν = 的幂律很好地描述-2.43 ± 0.06 或通过形状参数 Γ′ = 1.3 × 10-3 (km s-1)-1 在 z = 2.72 处的类 CDM 功率谱（所有误差条 1 σ）。与当今 P(k) 参数的对应关系取决于所采用的宇宙学。对于 Ωm = 0.4、ΩΛ = 0.6，最佳拟合形状参数为 γ = 0.16 h Mpc-1，与 2dF 星系红移巡天的测量结果非常一致，最佳拟合归一化为 σ8 = 0.82(γ/0.15)-0.44。在空间平坦的宇宙学模型中匹配观测到的星团质量函数和我们测量的 Δ2(kp) 需要 Ωm = 0.38 + 2.2(Γ - 0.15)。在 COBE 归一化、没有张量波动的平坦 CDM 模型中匹配 Δ2(kp) 需要 Ωm = (0.29 ± 0.04)n-2.89 h，满足此约束的模型也与我们测量的对数斜率一致。 Lyα森林通过限制其他方式无法获得的红移和长度尺度范围来补充线性物质功率谱的其他观测探测器，并且这些推断参数与独立估计的一致性为基于暴胀、冷暗物质和真空能量的宇宙学模型提供了进一步的支持。
We measure the filling factor, correlation function, and power spectrum of transmitted flux in a large sample of Lyα forest spectra, comprised of 30 Keck HIRES spectra and 23 Keck LRIS spectra. We infer the linear matter power spectrum P(k) from the flux power spectrum PF(k), using an improved version of the method of Croft et al. that accounts for the influence of redshift-space distortions, nonlinearity, and thermal broadening on the shape of PF(k). The evolution of the shape and amplitude of P(k) over the redshift range of the sample (z ≈ 2-4) is consistent with the predictions of gravitational instability, implying that nongravitational fluctuations do not make a large contribution to structure in the Lyα forest. Our fiducial measurement of P(k) comes from a subset of the data with 2.3 < z < 2.9, mean absorption redshift ⟨z⟩ = 2.72, and total path length Δz ≈ 25. It has a dimensionless amplitude Δ2(kp) = 0.74 at wavenumber kp = 0.03 (km s-1)-1 and is well described by a power law of index ν = -2.43 ± 0.06 or by a CDM-like power spectrum with shape parameter Γ′ = 1.3 × 10-3 (km s-1)-1 at z = 2.72 (all error bars 1 σ). The correspondence to present-day P(k) parameters depends on the adopted cosmology. For Ωm = 0.4, ΩΛ = 0.6, the best-fit shape parameter is Γ = 0.16 h Mpc-1, in good agreement with measurements from the 2dF Galaxy Redshift Survey, and the best-fit normalization is σ8 = 0.82(Γ/0.15)-0.44. Matching the observed cluster mass function and our measured Δ2(kp) in spatially flat cosmological models requires Ωm = 0.38 + 2.2(Γ - 0.15). Matching Δ2(kp) in COBE-normalized, flat CDM models with no tensor fluctuations requires Ωm = (0.29 ± 0.04)n-2.89 h, and models that satisfy this constraint are also consistent with our measured logarithmic slope. The Lyα forest complements other observational probes of the linear matter power spectrum by constraining a regime of redshift and length scale not accessible by other means, and the consistency of these inferred parameters with independent estimates provides further support for a cosmological model based on inflation, cold dark matter, and vacuum energy.