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Mitigating Internal Instrument Coupling for 21 cm Cosmology. II. A Method Demonstration with the Hydrogen Epoch of Reionization Array
Name
Kern_2020_ApJ_888_70.pdf
Description
Published version
Size
6.51 MB
Format
Adobe PDF
Checksum (MD5)
ff7b33c9ad9c6dd18ef08804605e4102
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Version
Final published version
Abstract
© 2020. The American Astronomical Society. All rights reserved. We present a study of internal reflection and cross-coupling systematics in Phase I of the Hydrogen Epoch of Reionization Array (HERA). In a companion paper, we outlined the mathematical formalism for such systematics and presented algorithms for modeling and removing them from the data. In this work, we apply these techniques to data from HERA's first observing season as a method demonstration. The data show evidence for systematics that, without removal, would hinder a detection of the 21 cm power spectrum for the targeted Epoch of Reionization (EoR) line-of-sight modes in the range 0.2 h -1 Mpc-1 < $" SRC="apjab5e8aieqn1.gif"/ < 0.5 h -1 Mpc-1. In particular, we find evidence for nonnegligible amounts of spectral structure in the raw autocorrelations that overlaps with the EoR window and is suggestive of complex instrumental effects. Through systematic modeling on a single night of data, we find we can recover these modes in the power spectrum down to the integrated noise floor, achieving a dynamic range in the EoR window of 106 in power (mK2 units) with respect to the bright galactic foreground signal. Future work with deeper integrations will help determine whether these systematics can continue to be mitigated down to EoR levels. For future observing seasons, HERA will have upgraded analog and digital hardware to better control these systematics in the field.
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DOI of Published Version
10.3847/1538-4357/AB5E8A
