Title:	An Overview of CHIME, the Canadian Hydrogen Intensity Mapping Experiment
Authors:	The CHIME Collaboration Amiri, Mandana Bandura, Kevin Boskovic, Anja Chen, Tianyue Cliche, Jean-François Deng, Meiling Denman, Nolan Dobbs, Matt Fandino, Mateus Foreman, Simon Halpern, Mark Hanna, David Hill, Alex S. Hinshaw, Gary Höfer, Carolin Kania, Joseph Klages, Peter Landecker, T. L. MacEachern, Joshua Masui, Kiyoshi Mena-Parra, Juan Milutinovic, Nikola Mirhosseini, Arash Newburgh, Laura Nitsche, Rick Ordog, Anna Pen, Ue-Li Pinsonneault-Marotte, Tristan Polzin, Ava Reda, Alex Renard, Andre Shaw, J. Richard Siege, Seth R. Singh, Saurabh Smega, Rick Tretyakov, Ian Gassen, Kwinten Van Vanderlinde, Keith Wang, Haochen Wiebe, Donald V. Willis, James S. Wulf, Dallas
Keywords:	Cosmology Baryon acoustic oscillations Radio telescopes Astronomical instrumentation Dark energy H I line emission Interferometric correlation Radio interferometers Telescopes
Issue Date:	1-Aug-2022
Publisher:	The American Astronomical Society
Citation:	The Astrophysical Journal Supplement Series,2022, Vol, 261, p29
Abstract:	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 0.8–2.5 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 × 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 three-quarters of the sky every day owing to Earth's rotation. An FX correlator utilizes field-programmable gate arrays and graphics processing units to digitize and correlate the signals, with different correlation products generated for cosmological, fast radio burst, pulsar, very long baseline interferometry, and 21 cm absorber back ends. For the cosmology back end, 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 3 yr 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.
Description:	Open Access
URI:	http://hdl.handle.net/2289/7981
ISSN:	0067-0049 1538-4365 (Online)
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2014SPIE.9145E..22B/abstract https://arxiv.org/abs/1406.2288 https://doi.org/10.3847/1538-4365/ac6fd9
Copyright:	2022 The Author(s)
Appears in Collections:	Research Papers (A&A)

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