Based on the latest SNe Ia data provided by Hicken et al. (2009) with using MLCS17 light curve fitter, together with the Baryon Acoustic Oscillation(BAO) and strong gravitational lenses(SGL), we investigate the constraints on the dark energy equation-of-state parameter $w$ in the flat universe, especially for the time-varying case $w(z)=w_0+w_zz/(1+z)$. The constraints from SNe data alone are found to be: (a) $(Ω_M, w)=(0.358, -1.09)$ as the best-fit results; (b) $(w_0, w_z)=(-0.73^{+0.23}_{-0.97}, 0.84^{+1.66}_{-10.34})$ for the two parameters in the time-varying case after marginalizing the parameter $Ω_M$; (c) the likelihood of parameter $w_z$ has a high non-Gaussian distribution; (d) an extra restriction on $Ω_M$ is necessary to improve the constraint of the SNe Ia data on the parameters ($w_0$, $w_z$). A joint analysis of SNe Ia data and BAO is made to break the degeneracy between $w$ and $Ω_M$, and leads to the interesting maximum likelihoods $w_0 = -0.94$ and $w_z = 0$. When marginalizing the parameter $Ω_M$, the fitting results are found to be $(w_0, w_z)=(-0.95^{+0.45}_{-0.18}, 0.41^{+0.79}_{-0.96})$. After adding the splitting angle statistic of SGL data, a consistent constraint is obtained $(Ω_M, w)=(0.298, -0.907)$ and the constraints on time-varying dark energy are further improved to be $(w_0, w_z) = (-0.92^{+0.14}_{-0.10}, 0.35^{+0.47}_{-0.54})$, which indicates that the phantom type models are disfavored.
Elucidating $Λ$CDM: Impact of Baryon Acoustic Oscillation Measurements on the Hubble Constant Discrepancy
我们研究了重子声振荡（BAO）尺度测量的影响之间的差异的哈勃常数（$H_0$）推断从本地距离阶梯和普朗克宇宙微波背景（CMB）数据。虽然单独的BAO数据不能约束$H_0$，但我们表明，将最新的BAO结果与WMAP，Atacama宇宙学望远镜（ACT）或南极望远镜（SPT）CMB数据相结合，产生的$H_0$值$2.4-3.1σ$低于距离阶梯，独立于普朗克，这种向下的拉力在一些早期的分析中不太明显，这些分析只使用了角度，平均BAO尺度约束，而不是完整的各向异性信息。同时，BAO和CMB数据的组合也不利于普朗克高多极温度功率谱所偏好的较低的$H_0$值。结合银河系和Lyman-$α$森林（Ly $α$）BAO与原始氘丰度的精确估计，得到了平坦$Λ$ CDM模型的$H_0=66.98\pm1.18$ km s $^{-1}$ Mpc $^{-1}$.这个值是完全独立的CMB各向异性的约束，是$3.0σ$低于最新的距离阶梯约束，虽然$2.4σ$张力也存在于星系BAO和LY $α$ BAO之间。这些结果表明，这是不可能的解释$H_0$的分歧，仅与普朗克数据的系统误差。事实上，即使在删除任何一个数据集之后，紧张局势仍然存在，这使得这个有趣的难题更加难以解决。
Inflation at the End of 2025: Constraints on $r$ and $n_s$ Using the Latest CMB and BAO Data
Sorbonne Université（索邦大学）；INAF/OAS Bologna（意大利国家天体物理研究所博洛尼亚天文台）；INFN, Sezione di Bologna（意大利国家核物理研究所博洛尼亚分部）；Université de Genève（日内瓦大学）；University of Sussex（萨塞克斯大学）；University of Melbourne（墨尔本大学）；California Institute of Technology（加州理工学院）
Joint Model-independent Constraints on the Post-Newtonian Parameter and Cosmic Curvature from Galaxy-scale Strong Lensing, SNe Ia, BAO, and Cosmic Chronometers
School of Microelectronics and Artificial Intelligence, Kaili University（凯里学院微电子与人工智能学院）；School of Physics and Electronics Science, Guizhou Normal University（贵州师范大学物理与电子科学学院）
Impact of a negative cosmological constant on the reconstruction of dark energy in light of DESI BAO data
School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS（杭州高等研究院基础物理与数学学院，UCAS）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；International Center for Theoretical Physics Asia-Pacific（亚太理论物理中心）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）
A measurement of the Hubble constant using galaxy redshift surveys
在一个平坦的$Λ$ CDM模型框架下，利用最新的6 dFGS、SDSS DR 7主星系样本、BOSS DR 12样本和eBOSS DR 14类星体样本的重子声振荡（BAO）测量结果，对哈勃常数$H_0$进行了测量.基于Kullback-Leibler（KL）分歧，我们检查了来自不同数据集的$H_0$值的一致性。我们发现，我们的测量是一致的，从普朗克和本地测量的$H_0$使用造父变星和Ia型超新星。我们进行预测$H_0$从未来的BAO测量，并发现，$H_0$的不确定性确定的未来BAO单独的数据，包括完整的eBOSS，DESI和欧几里得类，是可比的，从本地测量。
The Hubble tension and attempts to resolve it by modifying the physics of (or at) recombination motivate finding ways to determine $H_0$ and the sound horizon at the epoch of baryon decoupling $r_{\rm d}$ in ways that neither rely on a recombination model nor on late-time Hubble data. In this work, we investigate what one can learn from the current and future BAO data when treating $r_{\rm d}$ and $H_0$ as independent free parameters. It is well known that BAO gives exquisite constraints on the product $r_{\rm d}H_0$. We show here that imposing a moderate prior on $Ω_{\rm m} h^2$ breaks the de…
Constraints on $H_0$ from WMAP and baryon acoustic osillation measurements
本文报道了由威尔金森微波各向异性探测器（WMAP）结合最新的重子声学振荡（BAO）测量得到的PDMATHAMM的约束条件。我们使用6dF星系巡天（6dFGS），SDSS DR 7主星系样本（MGS），BOSS DR 12星系和eBOSS DR 14类星体的BAO测量。在WMAP宇宙微波背景辐射（CMB）数据中加入最近的BAO观测数据，我们将宇宙学参数$Ω_m=0.298\pm0.005$，$H_0=68.36^{+0.53}_{-0.52}$ km s $^{-1}$ Mpc $^{-1}$，$σ_8=0.8170^{+0.0159}_{-0.0175}$分别约束在空间平坦的$Λ$冷暗物质（CDM）模型中，将$Ω_m=0.302\pm0.008$，$H_0=67.63\pm1.30$ km s $^{-1}$ Mpc $^{-1}$，$σ_8=0.7988^{+0.0345}_{-0.0338}$约束在空间平坦的$w$ CDM模型中.在空间平坦的$w$ CDM模型中，来自CMB和BAO的对$w$的组合约束是$w=-0.96\pm0.07$。我们测量的$H_0$结果更倾向于低于70 km s的$^{-1}$ Mpc $^{-1}$值，与普朗克（2018）关于CMB约束的最新数据一致，但与Riess等人（2018）的局部测量结果存在$3.1\sim 3.5σ$张力。与WMAP单独分析相…
In this paper, we carry out a new model-independent cosmological test for the cosmic distance duality relation~(CDDR) by combining the latest five baryon acoustic oscillations (BAO) measurements and the Pantheon type Ia supernova (SNIa) sample. Particularly, the BAO measurement from extended Baryon Oscillation Spectroscopic Survey~(eBOSS) data release~(DR) 16 quasar sample at effective redshift $z=1.48$ is used, and two methods, i.e. a compressed form of Pantheon sample and the Artificial Neural Network~(ANN) combined with the binning SNIa method, are applied to overcome the redshift-matching …
We pursue a program to confront observations with inhomogeneous extensions of the FLRW metric. The main idea is to test the Copernican principle rather than assuming it a priori. We consider the $Λ$CDM model endowed with a spherical $Λ$LTB inhomogeneity around us, that is, we assume isotropy and test the hypothesis of homogeneity. We confront the $Λ$LTB model with the latest available data from CMB, BAO, type Ia supernovae, local $H_0$, cosmic chronometers, Compton y-distortion and kinetic Sunyaev-Zeldovich effect. We find that these data can constrain tightly this extra inhomogeneity, almost …
We propose a new coupled three-form dark energy model to relieve the Hubble tension in this paper. Firstly, by performing a dynamical analysis with the coupled three-form dark energy model, we obtain four fixed points, including a saddle point representing a radiation dominated Universe, a saddle point representing a matter dominated Universe, and two attractors representing two saturated de Sitter Universes. Secondly, by confronting the coupled three-form dark energy model and the $Λ$ cold dark matter model (the $Λ$CDM model) with cosmic microwave background (CMB), baryonic acoustic oscillati…
