On the use of temporal filtering for mitigating galactic synchrotron calibration bias in 21 cm reionization observations
Date Issued
2023
Author(s)
Ntsikelelo Charles
•
Nicholas Kern
•
•
Landman Bester
•
Oleg Smirnov
•
Nicolas Fagnoni
•
Eloy de Lera Acedo
Abstract
Precision antenna calibration is required for mitigating the impact of
foreground contamination in 21 cm cosmological radio surveys. One widely
studied source of error is the effect of missing point sources in the
calibration sky model; however, poorly understood diffuse galactic emission
also creates a calibration bias that can complicate the clean separation of
foregrounds from the 21 cm signal. In this work, we present a technique for
suppressing this bias with temporal filtering of radio interferometric
visibilities observed in a drift-scan mode. We demonstrate this technique on
mock simulations of the Hydrogen Epoch of Reionization Array (HERA) experiment.
Inspecting the recovered calibration solutions, we find that our technique
reduces spurious errors by over an order of magnitude. This improved accuracy
approaches the required accuracy needed to make a fiducial detection of the 21
cm signal with HERA, but is dependent on a number of external factors that we
discuss. We also explore different types of temporal filtering techniques and
discuss their relative performance and tradeoffs.
Volume
522
Issue
1
Start page
1009
Issn Identifier
0035-8711
Rights
open.access
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