Mapping of the neutral hydrogen (HI) 21-cm intensity fluctuations across redshifts promises a novel and powerful probe of cosmology. The neutral hydrogen gas mass density, $Ω_{\rm HI}$ and bias parameter, $b_{\rm HI}$ are key astrophysical inputs to the HI intensity fluctuation power spectrum. We compile the latest theoretical and observational constraints on $Ω_{\rm HI}$ and $b_{\rm HI}$ at various redshifts in the post-reionization universe. Constraints are incorporated from galaxy surveys, HI intensity mapping experiments, damped Lyman-$α$ system observations, theoretical prescriptions for assigning HI to dark matter halos, and the results of numerical simulations. Using a minimum variance interpolation scheme, we obtain the predicted uncertainties on the HI intensity fluctuation power spectrum across redshifts 0-3.5 for three different confidence scenarios. We provide a convenient tabular form for the interpolated values of $Ω_{\rm HI}$, $b_{\rm HI}$ and the HI power spectrum amplitude and their uncertainties. We discuss the consequences for the measurement of the power spectrum by current and future intensity mapping experiments.
The bispectrum is a 3-point statistic with the potential to provide additional information beyond power spectra analyses of survey datasets. Radio telescopes which broadly survey the 21cm emission from neutral hydrogen (HI) are a promising way to probe LSS and in this work we present an investigation into the HI intensity mapping (IM) bispectrum using simulations. We present a model of the redshift space HI IM bispectrum including observational effects from the radio telescope beam and 21cm foreground contamination. We validate our modelling prescriptions with measurements from robust IM simul…
Probing primordial non-Gaussianity with the power spectrum and bispectrum of future 21cm intensity maps
在再电离之后，星系中中性氢的21厘米发射线提供了暗物质的示踪物。使用SKA和其他射电望远镜进行的下一代强度测绘调查将覆盖大范围的天空区域和广泛的红移，便于将其用作原始非高斯性的探测器。{以前的工作已经表明，双谱可以实现对原始非高斯性的严格约束，未来的调查是专门设计用于干涉仪模式下的强度映射}。在这里，我们调查的约束条件，可从单碟模式下操作的调查，\rev{using the combined power spectrum and bispectrum signal}。在功率谱的情况下，单碟调查通常优于干涉仪调查。我们发现，相反的双谱：单碟调查是没有竞争力的干涉仪模式设计的调查。
Lyα Intensity Mapping in HETDEX: Galaxy-Lyα Intensity Cross-Power Spectrum
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Ludwig-Maximilians-Universität München（慕尼黑路德维希-马克西米利安大学）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo（东京大学宇宙起源研究科与先进研究院 Kavli 宇宙物理与数学研究所）；Instituto de Física de Cantabria (IFCA), CSIC-Univ. de Cantabria（坎塔布里亚物理研究所）；Universität Heidelberg, Institut für Theoretische Astrophysik, ZAH（海德堡大学）；Department of Astronomy & Astrophysics, The Pennsylvania State University（宾夕法尼亚州立大学天文学与天体物理学系）；Institute for Gravitation and the Cosmos, The Pennsylvania State University（宾夕法尼亚州立大学引力与宇宙研究所）
Observational Frontiers in the post-EoR 21-cm Intensity Mapping: Lessons from the SKA Pathfinders
Indian Institute of Technology Madras（印度马德拉斯理工学院）；Indian Institute of Technology Kharagpur（印度卡拉格普尔理工学院）；University of Manchester（曼彻斯特大学）；University of Western Cape（西开普敦大学）；McGill University（麦吉尔大学）；California Institute of Technology（加州理工学院）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Northeastern University（东北大学）；ETH Zurich（苏黎世联邦理工学院）；Indian Institute of Technology Indore（印度印多尔理工学院）；Arizona State University（亚利桑那州立大学）；Massachusetts Institute of Technology（麻省理工学院）；Perimeter Institute for Theoretical Physics（理论物理珀塞尔研究所）；University of Western Australia（西澳大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）
Beyond power spectrum to unveil systematics on HI intensity maps
University of Crete（克里特大学）；Foundation for Research and Technology - Hellas (FORTH)（希腊研究与技术基金会）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）；Università degli Studi di Torino（都灵大学）；INFN – Istituto Nazionale di Fisica Nucleare（意大利国家核物理研究所）；INAF – Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；University of the Western Cape（西开普大学）；Observatoire de la Cote d’Azur, Laboratoire Lagrange（蔚蓝海岸天文台拉格朗日实验室）
Intensity fluctuations of radio halo in galaxy cluster: Insights from power spectrum estimation
Indian Institute of Science（印度科学研究所）；New Mexico Institute of Mining and Technology（新墨西哥矿业与技术学院）；MIT Art, Design and Technology University（麻省理工学院艺术、设计与技术大学）；National Centre for Radio Astrophysics, Tata Institute of Fundamental Research（塔塔基础研究院国家射电天文学中心）；Manipal Centre for Natural Sciences, Manipal Academy of Higher Education（马尼拉高等教育学院自然科学中心）；Centre for Strings, Gravitation and Cosmology, Department of Physics, Indian Institute of Technology Madras（马德拉斯印度理工学院物理系弦论、引力与宇宙学中心）
Foreground contamination in Ly-alpha intensity mapping during the epoch of reionization
在再电离时期（EoR）的Ly-alpha发射的强度映射将受到来自较低红移的前景发射线的污染。计算了Ly-alpha发射在z~7处的平均强度和功率谱，并根据相关的天体物理过程估计了不确定度。我们发现，来自6563 A H-α，5007 A [OIII]和3727 A [OII]的低红移发射线将是观测到的Ly-alpha功率谱上的强污染物。我们利用恒星形成率（SFR）和光度函数（LF）来估计H-α在z~0.5处，[OIII]在z~0.9处和[OII]在z~1.6处的三条前景线的平均强度和功率谱，因为它们会污染z~7处的Ly-alpha发射。而这一点，也是最强的。我们分析了遮蔽的前景线高于一些线强度阈值的明亮的调查像素作为一种方式，以减少污染的强度映射调查。我们发现，如果我们去除通量大于1.4 × 10 ^-20 W/m^2的像素，前景污染可以忽略不计。
Measurements of the HI intensity mapping power spectrum at low redshifts with MIGHTEE data: comparison with detected HI galaxies
University of the Western Cape（西开普敦大学）；South African Radio Astronomy Observatory (SARAO)（南非射电天文观测台）；The University of Edinburgh（爱丁堡大学）；The University of Manchester（曼彻斯特大学）
The power spectrum of galaxies from large to small scales: a line-intensity mapping perspective
Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）；Institute for Computational Cosmology, Durham University（达勒姆大学计算宇宙学研究所）；Research Center for the Early Universe, Graduate School of Science, The University of Tokyo（东京大学理学研究科早期宇宙研究中心）
Probing sub-galactic mass structure with the power spectrum of surface-brightness anomalies in high-resolution observations of galaxy-galaxy strong gravitational lenses. II.Observational constraints on the sub-galactic matter power spectrum
