Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum
Journal
Date Issued
2020
Author(s)
Kern, Nicholas S.
•
Dillon, Joshua S.
•
Parsons, Aaron R.
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Carilli, Christopher L.
•
•
Abdurashidova, Zara
•
Aguirre, James E.
•
Alexander, Paul
•
Ali, Zaki S.
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Balfour, Yanga
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Beardsley, Adam P.
•
Billings, Tashalee S.
•
Bowman, Judd D.
•
Bradley, Richard F.
•
•
Burba, Jacob
•
Carey, Steven
•
Cheng, Carina
•
DeBoer, David R.
•
Dexter, Matt
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de Lera Acedo, Eloy
•
Ely, John
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Ewall-Wice, Aaron
•
Fagnoni, Nicolas
•
Fritz, Randall
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Furlanetto, Steve R.
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Gale-Sides, Kingsley
•
Glendenning, Brian
•
Gorthi, Deepthi
•
Greig, Bradley
•
Grobbelaar, Jasper
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Halday, Ziyaad
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Hazelton, Bryna J.
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Hewitt, Jacqueline N.
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Hickish, Jack
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Jacobs, Daniel C.
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Julius, Austin
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Kerrigan, Joshua
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Kittiwisit, Piyanat
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Kohn, Saul A.
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Kolopanis, Matthew
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Lanman, Adam
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La Plante, Paul
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Lekalake, Telalo
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Liu, Adrian
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MacMahon, David
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Malan, Lourence
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Malgas, Cresshim
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Maree, Matthys
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Martinot, Zachary E.
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Matsetela, Eunice
•
•
Molewa, Mathakane
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Morales, Miguel F.
•
Mosiane, Tshegofalang
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Murray, Steven G.
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Neben, Abraham R.
•
Nikolic, Bojan
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Nunhokee, Chuneeta D.
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Patra, Nipanjana
•
Pieterse, Samantha
•
Pober, Jonathan C.
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Razavi-Ghods, Nima
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Ringuette, Jon
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Robnett, James
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Rosie, Kathryn
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Sims, Peter
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Smith, Craig
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Syce, Angelo
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Thyagarajan, Nithyanandan
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Williams, Peter K. G.
•
Zheng, Haoxuan
Abstract
We discuss absolute calibration strategies for Phase I of the Hydrogen Epoch of Reionization Array (HERA), which aims to measure the cosmological 21 cm signal from the Epoch of Reionization. HERA is a drift-scan array with a 10° wide field of view, meaning bright, well-characterized point-source transits are scarce. This, combined with HERA's redundant sampling of the uv plane and the modest angular resolution of the Phase I instrument, make traditional sky-based and self-calibration techniques difficult to implement with high dynamic range. Nonetheless, in this work, we demonstrate calibration for HERA using point-source catalogs and electromagnetic simulations of its primary beam. We show that unmodeled diffuse flux and instrumental contaminants can corrupt the gain solutions and present a gain-smoothing approach for mitigating their impact on the 21 cm power spectrum. We also demonstrate a hybrid sky and redundant calibration scheme and compare it to pure sky-based calibration, showing only a marginal improvement to the gain solutions at intermediate delay scales. Our work suggests that the HERA Phase I system can be well calibrated for a foreground avoidance power spectrum estimator by applying direction-independent gains with a small set of degrees of freedom across the frequency and time axes.
Volume
890
Issue
2
Start page
122
Issn Identifier
0004-637X
Ads BibCode
2020ApJ...890..122K
Rights
open.access
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