Forthcoming photometric redshift surveys should provide an accurate probe of the acoustic peak in the two-point galaxy correlation function, in the form of angular clustering of galaxies within a given shell in redshift space. We investigate the form of the anticipated signal, quantifying the distortions that arise due to projection effects, and in particular explore the validity of applying the Limber approximation. A single-integral prescription is presented, which provides an alternative to Limber's equation, and produces a significantly improved prediction in the regime of interest.
The position of the acoustic peak within the angular correlation function relates to the angular diameter distance to the far side of the redshift bin. Thicker redshift bins therefore shift comoving features towards smaller angular scales. As a result, the value of the photometric redshift error acquires a greater significance, particularly at lower redshifts. In order to recover the dark energy equation of state to a level of 1%, we find the total redshift dispersion must be determined to within Δσ_z ~ 10^-3, which may prove challenging to achieve in practice.
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: Anisotropic Baryon Acoustic Oscillations measurements in Fourier-space with optimal redshift weights
利用扩展的重子振荡光谱巡天数据Release 14类星体样品,测量了具有最佳红移权的各向异性和各向同性的重子声学振荡(BAO)。应用红移权重将对BAO膨胀参数$α(z_{\rm eff})$的约束提高了17\ %。我们重建了$0.8<z<2.2$红移范围内BAO距离指标的演化历史。本文是分析eBOSS DR 14类星体样本的一组中的一部分。
Exploiting the shift of baryonic acoustic oscillations as a dynamical probe for dark interactions
星系和星系团的关联函数中的重子声峰为探测宇宙的时空几何提供了一把标准标尺,共同制约着角直径距离和哈勃膨胀率。此外,非线性效应可以系统地移动峰值位置,使我们有机会将这种聚集特征也作为动态探测来利用。我们调查的可能性,检测相互作用的黑暗部门通过准确测定重子声学标度。利用从CoDECS模拟中提取的公共晕目录-迄今为止最大的N体相互作用暗能量模型模拟套件-我们确定了重子尺度的位置,该位置适合带滤波关联函数,专门用于放大声音视界处的信号。在0 < z < 2的范围内,我们分析了由于非线性动力学、红移空间失真和高斯红移误差引起的位移。由于暗能量和暗物质之间的耦合以一种特殊的方式影响晕的成团特性,特别是重子声振荡的振幅和位置,重子峰位置的宇宙演化可能提供一种直接的方法来区分相互作用的暗能量模型和标准的ΛCDM框架。为了最大限度地提高重子峰作为动力学探测器的效率,必须在红移空间中测量关联函数,因为在红移空间中,由于非线性引起的重子声学位移被放大。光谱星系巡天的典型红移误差不会显著影响这些结果。
The Effect of Interstellar Absorption on Measurements of the Baryon Acoustic Peak in the Lyman-α Forest
近年来,人们利用氢Lyman-α森林的自相关性,利用BOSS巡天的数万条类星体谱,观测到了红移2 < z < 3.5的重子声峰。然而,银河系的星际介质会将吸收线引入任何河外源的光谱中。这些谱线虽然很弱,在单一BOSS光谱中无法检测到,但可能会使宇宙学信号产生偏差。为了检验这一点,我们通过叠加超过一百万个星系和类星体的光谱来生成吸收线图。我们发现,系统介绍太小,影响目前的重子声学峰值的准确性,但可能是相关的未来调查,如暗能量光谱仪(DESI)。我们概述了一种方法来解释这与未来的数据集。
Locating the missing baryons in the warm-hot intergalactic medium with fast radio bursts and the Sunyaev-Zel'dovich effect
School of Astronomy and Space Science, Nanjing University(南京大学天文与空间科学学院);Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education(教育部现代天文与天体物理重点实验室(南京大学));Department of Astronomy, School of Physical Sciences, University of Science and Technology of China(中国科学技术大学物理科学学院天文学系);Center for Cosmology and Computational Astrophysics, Zhejiang University(浙江大学宇宙学与计算天体物理中心)
Baryon Acoustic Oscillations and the Hubble Constant: Past, Present and Future
我们利用大爆炸核合成(BBN)的重子声学振荡(BAO)和重子密度测量研究了哈勃常数($H_0$)的约束。我们首先调查星系BAO测量和那些使用莱曼- $α$森林,贝叶斯框架内的紧张局势。使用eBOSS DR 14的最新结果,我们发现,假设平坦的$Λ$ CDM,该张力的概率为$\simeq6.3\%$。我们测量$H_0 = 67.6\pm1.1$ km s $^{-1}$ Mpc $^{-1}$,与一个弱的依赖于先前使用的BBN,与普朗克宇宙微波背景(CMB)的结果,并在强张力与距离阶梯的结果。最后,我们预测了未来的BAO $+$ BBN测量的$H_0$,使用暗能量光谱仪(DESI)。我们发现,BBN之前的选择将有显着的影响时,考虑未来的BAO测量DESI。
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Measuring D_A and H at z=0.57 from the Baryon Acoustic Peak in the Data Release 9 Spectroscopic Galaxy Sample
In an age of large astronomical dateset and severe cosmological tensions, the case for model independent analyses is compelling. We present a set of 14 baryon acoustic oscillations measurements in thin redshift shells with 3% precision that were obtained by analyzing BOSS DR12 and eBOSS DR16 galaxies in the redshift range $0.32<z<0.66$. Thanks to the use of thin shells, the analysis is carried out using just redshifts and angles so that the fiducial model is only introduced when considering the mock catalogs, necessary for the covariance matrix estimation and the pipeline validation. We compar…
A New Statistic for Analyzing Baryon Acoustic Oscillations
本文介绍了一种新的用于测量和分析大尺度结构,特别是重子声学振荡的统计ω_l。Ω_1是一种带滤波的、配置空间统计量,其易于实现,并且具有优于传统功率谱和关联函数估计器的优点。与这些估计器不同,omega_l可以将大部分声学信息定位到声学尺度处的单个凹陷中,同时还避免对约束不良的大尺度功率(即,积分约束)。它还通过对计数对各向异性聚类敏感,并且不需要任何分箱。我们测量的偏移声峰由于非线性效应,使用来自二次采样的暗物质目录,以及从模拟星系目录通过晕占据分布(HOD)建模。所有这些都是在z=1的1 h ^{-1}Gpc盒子中对1024^3粒子暗物质的44个模拟实现得出的。我们将这些位移与从功率谱中得到的位移进行了比较,并得出结论,结果一致。这表明从ω_0和P(k)获得的任何距离测量将彼此一致。我们还表明,它是可能的,以提取相同数量的声学信息使用ω_0或P(k)从等体积调查。
The baryon acoustic oscillation feature can be used as a standard cosmological ruler. In practice, for sub-percent level accuracy on the distance scale, it must be standardized. The physical reason why is understood, so we use this to develop an algorithm which improves the estimated scale. The algorithm exploits the fact that, over the range of scales where the initial correlation function is well-fit by a polynomial, the leading order effects which distort the length of the ruler can be accounted for analytically. Tests of the method in numerical simulations show that it provides simple and …
We study and compare fitting methods for the Lyman-$α$ (Ly$α$) forest 3D correlation function. We use the nested sampler PolyChord and the community code picca to perform a Bayesian analysis which we compare with previous frequentist analyses. By studying synthetic correlation functions, we find that the frequentist profile likelihood produces results in good agreement with a full Bayesian analysis. On the other hand, Maximum Likelihood Estimation with the Gaussian approximation for the uncertainties is inadequate for current data sets. We compute for the first time the full posterior distribu…
Roman Space Telescope will survey about 17 million emission-line galaxies over a range of redshifts. Its main targets are H$α$ emission-line galaxies at low redshifts and [O III] emission-line galaxies at high redshifts. The Roman Space Telescope will estimate the redshift these galaxies with single line identification. This suggests that other emission-line galaxies may be misidentified as the main targets. In particular, it is hard to distinguish between the H$β$ and [O III] lines as the two lines are close in wavelength and hence the photometric information may not be sufficient to separate…
Fitting Methods for Baryon Acoustic Oscillations in the Lyman-α Forest Fluctuations in BOSS Data Release 9
描述了分析莱曼-α森林涨落和测量重子声学振荡(BAO)参数的拟合方法。我们将我们的方法应用于BOSS Data Release 9。我们的方法是基于物理坐标空间中的三维关联函数模型,并包括红移空间失真,各向异性非线性展宽,和宽带失真的影响。我们允许独立的尺度因子沿和垂直的视线,以尽量减少对我们假设的基准宇宙学的依赖,并获得单独的测量的BAO角和相对速度尺度。我们的拟合软件和复制我们的主要BOSS数据版本9结果所需的输入文件是公开的。
Anisotropy in the matter distribution beyond the baryonic acoustic oscillation scale
利用星系两点关联函数追踪重子声学振荡(BAO)尺度的宇宙演化是目前探测早期暗能量最有希望的方法。许多正在进行和未来的实验将以前所未有的精度测量BAO峰值。我们表明,基于一组N体模拟的物质分布是各向异性的~150 Mpc/h,远远超出了BAO规模的~ 100 M pc/h,并讨论了对BAO测量的影响。为此目的,我们使用对准关联函数,即,高密度峰与沿着峰的取向和垂直于峰的取向测量的总体物质分布之间的关联函数关联函数。与传统的关联函数相比,高密度峰的取向(垂直于)被增强(减少)了约2倍,并且如果沿着相关函数测量,BAO峰的位置朝向更小(更大)的尺度移动。(垂直于)高密度峰的取向。类似的影响,预计形状观测星系关联函数在BAO尺度。
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Observational systematics and baryon acoustic oscillations in the correlation function
我们提出了重子声学振荡(BAO)尺度的测量确定的120万个大质量星系的红移0.2 < z < 0.75分布在9300平方度的集群,量化的红移空间关联函数。为了方便这些测量,我们定义,描述,并激励选择功能的SDSS III重子振荡光谱巡天(BOSS)的最终数据发布(DR 12)的星系。这包括观测足迹,图像质量和银河系消光的掩模,以及考虑调查成像和光谱部分固有的密度关系的权重。我们模拟了模拟星系样本中观察到的系统趋势,并证明它们对重子声学振荡(BAO)尺度测量没有影响,并且对恢复的统计不确定性有轻微的影响。我们在0.2 < z < 0.5,0.5 < z < 0.75和(重叠)0.4 < z < 0.6红移箱中测量横向和径向BAO距离测量。在每个红移箱,我们得到的精度是2.7%或更好的径向距离和1.6%或更好的横向距离。红移仓的组合表示径向距离的1.8%精度和横向距离的1.1%精度。本文是分析BOSS最终星系聚类数据集的一部分。这里提出的测量和可能性与Alam et al.(2016)中的其他测量和可能性相结合,以产生BOSS的最终宇宙学约束。
The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations at redshift of 0.72 with the DR14 Luminous Red Galaxy Sample