1. The necessity of individually validated beam models for an interferometric epoch of reionization detection.
- Author
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Chokshi, A, Barry, N, Line, J L B, Jordan, C H, Pindor, B, and Webster, R L
- Subjects
RADIO interferometers ,RADIO measurements ,AGE of stars ,MIDDLE Ages ,POWER spectra - Abstract
A first statistical detection of the 21-cm Epoch of Reionization (EoR) is on the horizon, as cosmological volumes of the Universe become accessible via the adoption of low-frequency interferometers. We explore the impact which non-identical instrumental beam responses can have on the calibrated power spectrum and a future EoR detection. All-sky satellite measurements of Murchison Widefield Array (MWA) beams have revealed significant sidelobe deviations from cutting-edge electromagnetic simulations at the |${\sim} 10~{{\ \rm per\ cent}}$| zenith power level. By generating physically motivated deformed beam models, we emulate real measurements of the MWA which inherently encode the imprints of varied beams. We explore two calibration strategies: using a single beam model across the array, or using a full set of deformed beams. Our simulations demonstrate beam-induced leakage of foreground power into theoretically uncontaminated modes, at levels which exceed the expected cosmological signal by factors of over |$\sim$| 1000 between the modes k = 0.1–1 |$h\mathrm{Mpc}^{-1}$|. We also show that this foreground leakage can be mitigated by including measured models of varied beams into calibration frameworks, reducing the foreground leakage to a sub-dominant effect and potentially unveiling the EoR. Finally, we outline the future steps necessary to make this approach applicable to real measurements by radio interferometers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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