Measuring HERA's primary beam in-situ: methodology and first results
Abstract
The central challenge in 21~cm cosmology is isolating the cosmological signal from bright foregrounds. Many separation techniques rely on the accurate knowledge of the sky and the instrumental response, including the antenna primary beam. For drift-scan telescopes such as the Hydrogen Epoch of Reionization Array \citep[HERA, ][]{DeBoer2017} that do not move, primary beam characterization is particularly challenging because standard beam-calibration routines do not apply \citep{Cornwell2005} and current techniques require accurate source catalogs at the telescope resolution. We present an extension of the method from \citet{Pober2012} where they use beam symmetries to create a network of overlapping source tracks that break the degeneracy between source flux density and beam response and allow their simultaneous estimation. We fit the beam response of our instrument using early HERA observations and find that our results agree well with electromagnetic simulations down to a -20~dB level in power relative to peak gain for sources with high signal-to-noise ratio. In addition, we construct a source catalog with 90 sources down to a flux density of 1.4~Jy at 151~MHz.
Cite
@article{arxiv.2005.12174,
title = {Measuring HERA's primary beam in-situ: methodology and first results},
author = {Chuneeta D. Nunhokee and Aaron R. Parsons and Nicholas S. Kern and Bojan Nikolic and Jonathan C. Pober and Gianni Bernardi and Chris L. Carilli and Zara Abdurashidova and James E. Aguirre and Paul Alexander and Zaki S. Ali and Yanga Balfour and Adam P. Beardsley and Tashalee S. Billings and Judd D. Bowman and Richard F. Bradley and Jacob Burba and Carina Cheng and David R. DeBoer and Matt Dexter and Eloy de~Lera~Acedo and Joshua S. Dillon and Aaron Ewall-Wice and Nicolas Fagnoni and Randall Fritz and Steve R. Furlanetto and Kingsley Gale-Sides and Brian Glendenning and Deepthi Gorthi and Bradley Greig and Jasper Grobbelaar and Ziyaad Halday and Bryna J. Hazelton and Jacqueline N. Hewitt and Daniel C. Jacobs and Austin Julius and Joshua Kerrigan and Piyanat Kittiwisit and Saul A. Kohn and Matthew Kolopanis and Adam Lanman and Paul La~Plante and Telalo Lekalake and Adrian Liu and David MacMahon and Lourence Malan and Cresshim Malgas and Matthys Maree and Zachary E. Martinot and Eunice Matsetela and Andrei Mesinger and Mathakane Molewa and Miguel F. Morales and Tshegofalang Mosiane and Abraham R. Neben and Nipanjana Patra and Samantha Pieterse and Nima Razavi-Ghods and Jon Ringuette and James Robnett and Kathryn Rosie and Peter Sims and Craig Smith and Angelo Syce and Nithyanandan Thyagarajan and Peter K. ~G. Williams and Haoxuan Zheng},
journal= {arXiv preprint arXiv:2005.12174},
year = {2020}
}
Comments
22 pages, 22 figures, accepted for publication in ApJ