Cosmological implications of baryon acoustic oscillation measurements
Cosmological implications of baryon acoustic oscillation measurements
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DOI：
10.1103/physrevd.92.123516
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发表时间：
2015-12-14
影响因子：
5
通讯作者：
Zhao, Gong-Bo
中科院分区：
文献类型：
--
作者：
Aubourg, Eric;Bailey, Stephen;Zhao, Gong-Bo
我们从重子声振荡(BAO)测量与宇宙微波背景(CMB)数据和最近对Ia型超新星(SN)数据的重新分析相结合，得出了对宇宙学参数的限制和暗能量模型的测试。特别是，我们利用了SDSS-III重子振荡光谱调查(BOSS)中来自星系团和莱曼-阿尔法森林(LyaF)的高精度BaO测量。将Bao标尺视为未校准的标准标尺，仅Bao数据就能产生对暗能量的高度可信的探测；与CMB角声标尺相结合，它们进一步意味着宇宙几乎是平的。加上CMB定标的声层物理尺度，将BAO和SN数据组合成“反距离阶梯”，得到H-0=67.3+/-1.1公里S(-1)MPC(-1)，精度为1.7%。这一测量假设了标准的结合前物理，但对暗能量或空间曲率的假设不敏感，因此与基于CMB的假设平坦的Lambda CDM宇宙学的估计一致是对这一最小宇宙学模型的重要佐证。对于恒定暗能量，我们的BaO+SN+CMB组合得到物质密度欧米伽(M)=0.301+/-0.008，曲率欧米伽(K)=-0.003+/-0.003。当我们允许更一般形式的演化暗能量时，BaO+SN+CMB参数约束总是与平坦的Lambda CDM值在大约1西格玛时一致。虽然模型拟合的总体CHI(2)令人满意，但LyaF Bao的测量与模型预测处于中等(2-2.5西格玛)紧张状态。具有早期暗能量的模型在高红移时跟踪主要能量分量，仍然与我们的膨胀历史约束一致，并且它们产生了更高的H-0和更低的物质聚集幅度，这与一些低红移观测结果更好地吻合。单单是膨胀历史就给出了中微子物种的总质量的上限，Sigma m(Nu)<；0.56 eV(95%置信度)，如果我们将透镜信号包括在普朗克CMB功率谱中，则提高到Sigma m(Nu)<；0.25 eV。在一个允许额外相对论物种的扁平Lambda CDM模型中，我们的数据组合得到N-Jeff=3.43+/-0.26；而LyaF Bao数据在排除BaO星系时倾向于更高的N-Jeff，而只有BaO星系倾向于N-ff近似为3。当结构增长从CMB向前推断到低红移时，受我们数据约束的标准暗能量模型预测的物质聚集水平高于大多数(但不是全部)观测估计。
We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) data and a recent reanalysis of Type Ia supernova (SN) data. In particular, we take advantage of high-precision BAO measurements from galaxy clustering and the Lyman-alpha forest (LyaF) in the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Treating the BAO scale as an uncalibrated standard ruler, BAO data alone yield a high confidence detection of dark energy; in combination with the CMB angular acoustic scale they further imply a nearly flat universe. Adding the CMB-calibrated physical scale of the sound horizon, the combination of BAO and SN data into an "inverse distance ladder" yields a measurement of H-0 = 67.3 +/- 1.1 km s(-1) Mpc(-1), with 1.7% precision. This measurement assumes standard prerecombination physics but is insensitive to assumptions about dark energy or space curvature, so agreement with CMB-based estimates that assume a flat Lambda CDM cosmology is an important corroboration of this minimal cosmological model. For constant dark energy (Lambda), our BAO + SN + CMB combination yields matter density Omega(m) = 0.301 +/- 0.008 and curvature Omega(k) = -0.003 +/- 0.003. When we allow more general forms of evolving dark energy, the BAO + SN + CMB parameter constraints are always consistent with flat Lambda CDM values at approximate to 1 sigma. While the overall chi(2) of model fits is satisfactory, the LyaF BAO measurements are in moderate (2-2.5 sigma) tension with model predictions. Models with early dark energy that tracks the dominant energy component at high redshift remain consistent with our expansion history constraints, and they yield a higher H-0 and lower matter clustering amplitude, improving agreement with some low redshift observations. Expansion history alone yields an upper limit on the summed mass of neutrino species, Sigma m(nu) < 0.56 eV (95% confidence), improving to Sigma m(nu) < 0.25 eV if we include the lensing signal in the Planck CMB power spectrum. In a flat Lambda CDM model that allows extra relativistic species, our data combination yields N-eff = 3.43 +/- 0.26; while the LyaF BAO data prefer higher N-eff when excluding galaxy BAO, the galaxy BAO alone favor N-eff approximate to 3. When structure growth is extrapolated forward from the CMB to low redshift, standard dark energy models constrained by our data predict a level of matter clustering that is high compared to most, but not all, observational estimates.