We re-analyze data from the gravitational-wave event GW170817 and its host galaxy NGC4993 to demonstrate the importance of accurate total and peculiar velocities when measuring the Hubble constant using this nearby Standard Siren. We show that a number of reasonable choices can be made to estimate the velocities for this event, but that systematic differences remain between these measurements depending on the data used. This leads to significant changes in the Hubble constant inferred from GW170817. We present Bayesian Model Averaging as one way to account for these differences, and obtain $H_{0}=66.8^{+13.4}_{-9.2}\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$. Adding additional information on the viewing angle from high resolution imaging of the radio counterpart refines this to $H_{0}=64.8^{+7.3}_{-7.2}\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$. During this analysis we also present an alternative Bayesian model for the posterior on $H_{0}$ from Standard Sirens that works more closely with observed quantities from redshift and peculiar velocity surveys. Our results more accurately capture the true uncertainty on the total and peculiar velocities of NGC4993 and show that exploring how well different datasets characterize galaxy groups and the velocity field in the local Universe could improve this measurement further. These considerations impact any low-redshift distance measurement, and the improvements we suggest here can also be applied to standard candles like type Ia supernovae. GW170817 is particularly sensitive to peculiar velocity uncertainties because it is so close. For future standard siren measurements the importance of this error will decrease as (a) we will measure more distant standard sirens, and (b) the random direction of peculiar velocities will average out with more detections.
An accurate method to determine the systematics due to the peculiar velocities of galaxies in measuring the Hubble constant from gravitational wave standard sirens
Probing the environment around GW170817 with DESI: insights on galaxy group peculiar velocities for standard siren measurements
Carnegie Mellon University（卡内基梅隆大学）；University of Rochester（罗切斯特大学）；University of Queensland（昆士兰大学）；SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；Siena University（锡耶纳大学）；Stanford University（斯坦福大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Boston University（波士顿大学）；University College London（伦敦大学学院）；Korea Astronomy and Space Science Institute（韩国天文与空间科学研究所）；NSF NOIRLab（美国国家光学-红外天文研究实验室）；University of Toronto（多伦多大学）；University of Pittsburgh（匹兹堡大学）；The Barcelona Institute of Science and Technology（巴塞罗那科学技术研究院）；University of Portsmouth（朴茨茅斯大学）；ICE-CSIC（宇宙学与统计物理研究所）；University of Virginia（弗吉尼亚大学）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；The Ohio State University（俄亥俄州立大学）；The University of Texas at Dallas（德克萨斯大学达拉斯分校）；Southern Methodist University（南方卫理公会大学）
A Pixelated Approach to Galaxy Catalogue Incompleteness: Improving the Dark Siren Measurement of the Hubble Constant
利用引力波标准警报器进行宇宙学分析已成为众所周知的事情，人们对测量哈勃常数$H_0$特别感兴趣，并对当前早期和晚期测量之间的紧张关系进行了说明。目前的紧张局势是超过$4σ$和标准警报器将能够提供一个完全独立的测量。暗警报（没有电磁对应物的双黑洞或中子星合并）可以提供信息，如果丢失的红移信息通过使用星系目录来识别合并的潜在宿主星系。然而，星系目录的不完整性影响这一分析，它的准确建模是必不可少的$H_0$获得一个公正的测量。以前，这是通过假设引力波事件的天空区域内的均匀完整性来实现的。本文提出了一种更新的方法，其中的星系目录的完整性估计在一个方向依赖的问题，通过像素化的天空和计算的完整性的星系目录沿每条视线。单个事件的$H_0$推断是在逐像素的基础上执行的，并且像素被组合以获得最终结果。对第一个引力波瞬变目录（GWTC-1）中的事件进行重新分析，结果表明，与等效LIGO和Virgo结果的68.3%最高密度间隔相比，$H_0$的测量值提高了约5%，$H_0$的测量值为$H_0= 68.8^{+15.9}_{-7.8}$ km s $^{-1}$ Mpc $^{-1}$。
Mind the peak: improving cosmological constraints from GWTC-4.0 spectral sirens using semiparametric mass models
Università di Bologna（博洛尼亚大学）；INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（博洛尼亚天文物理与空间科学研究所）；INFN - Sezione di Bologna（博洛尼亚意大利国家核物理研究所）
Enhancing dark siren cosmology via Gaussian process reconstruction of incomplete galaxy catalogs
Università di Bologna（博洛尼亚大学）；INFN - Sezione di Bologna（意大利国家核物理研究所博洛尼分所）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）
Clustering effects on the Dark Siren determination of $H_0$: A simulation study
University of Edinburgh（爱丁堡大学）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Max Planck Institute for Gravitational Physics（马克斯·普朗克引力物理学研究所）；Leiden University（莱顿大学）
Constraining cosmological simulations with peculiar velocities: a forward-modeling approach
Aix Marseille Université（艾克斯-马赛大学）；CNRS/IN2P3, CPPM（法国国家科学研究中心/法国国家粒子物理研究所，粒子与核物理中心）；Leibniz-Institut für Astrophysik Potsdam（波茨坦莱布尼茨天体物理研究所）；Racah Institute of Physics, Hebrew University（希伯来大学雷卡物理学研究所）；Institut de Recherche sur les Lois Fondamentales de l’Univers, CEA, Universite’ Paris-Saclay（CEA巴黎萨克雷大学基础宇宙定律研究所）；University of Oxford（牛津大学）；Institute for Astronomy, University of Hawaii（夏威夷大学天文学研究所）
Approximating the peculiar velocity distribution of dark matter halos with Tsallis statistics
Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS（中国科学院南美天文中心，国家天文台）；Key Laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences（计算天体物理重点实验室，国家天文台，中国科学院）
