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.

22 pages, 22 figures, accepted for publication in ApJ

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Cited by in corpus (8)

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• Dual Polarization Measurements of MWA Beampatterns at 137 MHz
• Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum
• A Differentiable, End-to-End Forward Model for 21 cm Cosmology: Estimating the Foreground, Instrument, and Signal Joint Posterior
• Strategy for mitigation of systematics for EoR experiments with the Murchison Widefield Array
• Robust direction-dependent gain-calibration of beam-modelling errors far from the target field
• Synthetic Observations with the Square Kilometre Array (SKA) -- development towards an end-to-end pipeline
• Drone Beam Mapping of the TONE Radio Dish Array