An Overview of CHIME, the Canadian Hydrogen Intensity Mapping Experiment
The CHIME Collaboration, Mandana Amiri, Kevin Bandura, Anja Boskovic, Tianyue Chen, Jean-François Cliche, Meiling Deng, Nolan Denman, Matt Dobbs, Mateus Fandino… 展开作者
The CHIME Collaboration, Mandana Amiri, Kevin Bandura, Anja Boskovic, Tianyue Chen, Jean-François Cliche, Meiling Deng, Nolan Denman, Matt Dobbs, Mateus Fandino, Simon Foreman, Mark Halpern, David Hanna, Alex S. Hill, Gary Hinshaw, Carolin Höfer, Joseph Kania, Peter Klages, T. L. Landecker, Joshua MacEachern, Kiyoshi Masui, Juan Mena-Parra, Nikola Milutinovic, Arash Mirhosseini, Laura Newburgh, Rick Nitsche, Anna Ordog, Ue-Li Pen, Tristan Pinsonneault-Marotte, Ava Polzin, Alex Reda, Andre Renard, J. Richard Shaw, Seth R. Siegel, Saurabh Singh, Rick Smegal, Ian Tretyakov, Kwinten Van Gassen, Keith Vanderlinde, Haochen Wang, Donald V. Wiebe, James S. Willis, Dallas Wulf
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a drift scan radio telescope operating across the 400-800 MHz band. CHIME is located at the Dominion Radio Astrophysical Observatory near Penticton, BC Canada. The instrument is designed to map neutral hydrogen over the redshift range 0.8 to 2.5 to constrain the expansion history of the Universe. This goal drives the design features of the instrument. CHIME consists of four parallel cylindrical reflectors, oriented north-south, each 100 m $\times$ 20 m and outfitted with a 256 element dual-polarization linear feed array. CHIME observes a two degree wide stripe covering the entire meridian at any given moment, observing 3/4 of the sky every day due to Earth rotation. An FX correlator utilizes FPGAs and GPUs to digitize and correlate the signals, with different correlation products generated for cosmological, fast radio burst, pulsar, VLBI, and 21 cm absorber backends. For the cosmology backend, the $N_\mathrm{feed}^2$ correlation matrix is formed for 1024 frequency channels across the band every 31 ms. A data receiver system applies calibration and flagging and, for our primary cosmological data product, stacks redundant baselines and integrates for 10 s. We present an overview of the instrument, its performance metrics based on the first three years of science data, and we describe the current progress in characterizing CHIME's primary beam response. We also present maps of the sky derived from CHIME data; we are using versions of these maps for a cosmological stacking analysis as well as for investigation of Galactic foregrounds.
Flux Density Calibration of Radio Bursts Detected in the Sidelobes of the Canadian Hydrogen Intensity Mapping Experiment
York University（约克大学）；ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；UvA（阿姆斯特丹大学）；MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究研究所）；Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理学系）；Laboratoire d’Astrophysique de Marseille, Aix-Marseille Univ.（马赛天体物理实验室，艾克斯-马赛大学）
Holographic Beam Mapping of the CHIME Pathfinder Array
加拿大氢强度测绘实验（CHIME）探路者射电望远镜目前正在400至800兆赫之间测量北半球。通过对中性氢在$z \sim 0.8-2.5$ CHIME之间的红移21厘米谱线的测量，绘制出中性氢的大尺度结构图，将有助于我们对暗能量的理解。明亮的天体物理前景必须从中性氢信号中分离出来，这一任务需要对偏振的望远镜光束进行精确的表征。使用DRAO John A. Galt26米望远镜，我们已经开发了一种全息仪器和技术映射CHIME探路者光束.我们报告的文书和这一努力的初步成果的状态。
CHIME/Slow overview and pilot survey: A new backend to search for second-duration radio transients with the CHIME telescope
Tata Institute of Fundamental Research（塔塔基础研究所）；Raman Research Institute（拉曼研究所）；LUX, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS（巴黎天文台，巴黎文理研究大学，索邦大学，法国国家科学研究中心）；National Centre for Radio Astrophysics（国家射电天体物理中心）；Indian Institute of Astrophysics（印度天体物理研究所）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内克天文研究所）；ASTRON, the Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；York University（约克大学）
Characterization of the John A. Galt telescope for radio holography with CHIME
加拿大氢强度测绘实验（CHIME）将测量天体物理中性氢的21厘米发射，以探测红移z = 0.8 - 2.5的大尺度结构。然而，在明显更明亮的前景下检测21厘米的信号仍然是一个关键挑战。由于21厘米和前景发射之间的高动态范围，需要对仪器系统进行精密校准，特别是望远镜光束，以成功地过滤出前景。用于实现CHIME波束的高保真度测量的一种技术是无线电全息术，其中来自CHIME的每个模拟输入的信号与来自共同定位的参考天线（26 m John A. 26米的Galt望远镜跟踪一个经过CHIME的亮点源。在这项工作中，我们提出了一个分析的几个Galt望远镜的属性。我们采用漂移扫描测量的几个明亮的来源，以及来自408 MHz Haslam地图的背景估计，估计Galt系统的温度。为了确定Galt望远镜的光束形状，我们对明亮的射电源仙后座A进行了光栅扫描并进行了分析。最后，我们使用早期的全息测量来测量高尔特望远镜的几何形状相对于CHIME的CHIME和高尔特干涉数据集的全息分析。
Overview of the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD) Project
West Virginia University（西弗吉尼亚大学）；University of Calgary（卡尔加里大学）；McGill University（麦吉尔大学）；INAF – Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；Rhodes University（罗德斯大学）；South African Radio Astronomy Observatory（南非射电天文台）；Queen’s University（女王大学）；University of British Columbia, Okanagan Campus（不列颠哥伦比亚大学奥肯那根校区）；Dunlap Institute for Astronomy & Astrophysics, University of Toronto（多伦多大学邓普天文学与天体物理学研究所）；David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto（多伦多大学大卫·A·邓普克天文学与天体物理学系）；Arizona State University（亚利桑那州立大学）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内库克天文学研究所）；ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所ASTRON）
McGill University（麦吉尔大学）；Massachusetts Institute of Technology（麻省理工学院）；West Virginia University（西弗吉尼亚大学）；Carnegie Mellon University（卡内基梅隆大学）；National Centre for Radio Astrophysics（国家射电天体物理中心）；National Research Council of Canada（加拿大国家研究委员会）
The CHIME/FRB Outriggers: Commissioning the Hat Creek Outrigger and an Updated Calibration Scheme for Mitigating RFI
ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内科克天文学研究所）；MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理学与空间研究研究所）；Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理学系）
本文介绍 CHIME/FRB Outrigger 中 Hat Creek Outrigger 的调试，采用高斯过程回归校准方案缓解射频干扰，将点源灵敏度提升约 1.69-1.87 倍，并验证了该框架对大型干涉阵列的适用性。
