Robustness of baryon acoustic oscillation constraints for early-Universe modifications of ΛCDM cosmology
Robustness of baryon acoustic oscillation constraints for early-Universe modifications of ΛCDM cosmology
复制标题
DOI：
10.1103/physrevd.102.123515
复制
发表时间：
2020-12
影响因子：
5
通讯作者：
J. Bernal;Tristan L. Smith;K. Boddy;M. Kamionkowski
中科院分区：
文献类型：
--
作者：
J. Bernal;Tristan L. Smith;K. Boddy;M. Kamionkowski
重子声振荡（BAO）提供了一个强有力的标准标尺，可以用来限制宇宙在低红移的膨胀历史。标准的BAO分析返回一个独立于模型的测量膨胀率和同向角直径的距离作为红移的函数，标准化的辐射阻力的声音地平线。然而，这种方法依赖于固定的、预先计算的模板（在给定的基准宇宙学中获得）的各向异性距离失真，以便拟合观测结果。因此，共识的扩展可能会对模板拟合无法捕获的BAO特征做出贡献。我们进行模拟BAO适合功率谱计算假设宇宙学模型，修改扰动的增长之前重组，以测试标准BAO分析的鲁棒性。我们没有发现显着的偏差，在BAO分析的研究模型（自由有效数量的相对论性物种，早期的暗能量，中微子和一小部分的暗物质之间的相互作用的模型），即使是不提供一个很好的配合toPlanck测量的宇宙微波背景功率谱的情况下。这一结果支持使用标准的BAO分析和测量进行宇宙学参数推断和约束奇异模型。此外，我们还提供了一种方法来重现我们对不同模型和调查的研究，并讨论了处理BAO测量中最终偏差的不同选择。
Baryon acoustic oscillations (BAO) provide a robust standard ruler and can be used to constrain the expansion history of the Universe at low redshift. Standard BAO analyses return a model-independent measurement of the expansion rate and the comoving angular diameter distance as a function of redshift, normalized by the sound horizon at radiation drag. However, this methodology relies on anisotropic distance distortions of a fixed, precomputed template (obtained in a given fiducial cosmology) in order to fit the observations. Therefore, it may be possible that extensions to the consensusadd contributions to the BAO feature that cannot be captured by the template fitting. We perform mock BAO fits to power spectra computed assuming cosmological models that modify the growth of perturbations prior to recombination in order to test the robustness of the standard BAO analysis. We find no significant bias in the BAO analysis for the models under study (with a free effective number of relativistic species, early dark energy, and a model with interactions between neutrinos and a fraction of the dark matter), even for cases that do not provide a good fit toPlanckmeasurements of the cosmic microwave background power spectra. This result supports the use of the standard BAO analysis and its measurements to perform cosmological parameter inference and to constrain exotic models. In addition, we provide a methodology to reproduce our study for different models and surveys, as well as discuss different options to handle eventual biases in the BAO measurements.