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The 21-cm signal from the Epoch of Reionization (EoR) is a powerful probe of the evolution of the Universe. However, accurate measurements of the EoR signal from radio interferometric observations are sensitive to efficient foreground…

Instrumentation and Methods for Astrophysics · Physics 2025-09-23 Madhurima Choudhury , Jonathan C. Pober

We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Steven G. Murray , Cathryn M. Trott , Christopher H. Jordan

The 21 cm intensity mapping provides a promising probe of the large-scale structure. Astrophysical foregrounds, as the main source of contamination to the cosmological 21 cm signal, persist in a wedge-like region of Fourier space due to the…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-04 Kaifeng Yu , Xin Wang

The Epoch of Reionization (EoR) and Cosmic Dawn (CD) are pivotal stages during the first billion years of the universe, exerting a significant influence on the development of cosmic structure. The detection of the redshifted 21-cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Anshuman Tripathi , Abhirup Datta , Aishrila Mazumder , Suman Majumdar

The Murchison Widefield Array is a low-frequency Square Kilometre Array precursor located at the Murchison Radio-astronomy Observatory in Western Australia. Primarily designed as an imaging telescope, but with a flexible signal path, the…

Instrumentation and Methods for Astrophysics · Physics 2019-08-15 S. M. Ord , S. E. Tremblay , S. J. McSweeney , N. D. R. Bhat , C. Sobey , D. A. Mitchell , P. J. Hancock , F. Kirsten

Measurements with widefield radio interferometers often include the near-infinite gradient between the sky and the horizon. This causes aliasing inherent to the measurement itself, and is purely a consequence of the Fourier basis. For this…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-05 N. Barry , J. L. B. Line , C. R. Lynch , M. Kriele , J. Cook

The first generation of redshifted 21 cm detection experiments, carried out with arrays like LOFAR, MWA and GMRT, will have a very low signal-to-noise ratio per resolution element (\sim 0.2). In addition, whereas the variance of the…

We present an analysis of Epoch of Reionization data from Phase II of the Murchison Widefield Array using the \texttt{simpleDS} delay spectrum pipeline. Prior work analyzed the same observations using the FHD/$\varepsilon$ppsilon imaging…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-05 Matthew Kolopanis , Jonathan Pober , Daniel C. Jacobs , Samantha McGraw

Current attempts to measure the 21cm Power Spectrum of neutral hydrogen during the Epoch of Reionization are limited by systematics which produce measured upper limits above both the thermal noise and the expected cosmological signal. These…

The precise characterization and mitigation of systematic effects is one of the biggest roadblocks impeding the detection of the fluctuations of cosmological 21cm signals. Missing data in radio cosmological experiments, often due to radio…

The upcoming Square Kilometre Array Low Frequency (SKA-Low) interferometer will have the required sensitivity to detect the 21 cm line from neutral hydrogen during the Epoch of Reionisation (EoR). In preparation, we investigated the…

Instrumentation and Methods for Astrophysics · Physics 2025-09-25 E. Jong , C. Trott , C. D. Nunhokee , Q. Zheng

We explore the properties of interferometric data from high-redshift 21~cm measurements using the Murchison Widefield Array. These data contain redshifted 21~cm signal, contamination from continuum foreground sources, and radiometric noise.…

The compact configuration of Phase II of the Murchison Widefield Array (MWA) consists of both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model and redundant interferometric calibration.…

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;…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-19 Ntsikelelo Charles , Nicholas Kern , Gianni Bernardi , Landman Bester , Oleg Smirnov , Nicolas Fagnoni , Eloy de Lera Acedo

Global 21cm cosmology aims to investigate the cosmic dawn and epoch of reionisation by measuring the sky averaged HI absorption signal, which requires, accurate modelling of, or correction for, the bright radio foregrounds and distortions…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Dominic Anstey , Eloy de Lera Acedo , Will Handley

Statistical observations of the Epoch of Reionization using the 21 cm line of neutral hydrogen have the potential to revolutionize our understanding of structure formation and the first luminous objects. However, these observations are…

Astrophysics · Physics 2008-11-26 Miguel F. Morales , Judd D. Bowman , Jacqueline N. Hewitt

Tomography of redshifted 21 cm transition from neutral Hydrogen using Fourier synthesis telescopes is a promising tool to study the Epoch of Reionization (EoR). Limiting the confusion from Galactic and Extragalactic foregrounds is critical…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Harish Vedantham , N. Udaya Shankar , Ravi Subrahmanyan

A number of experiments are currently working towards a measurement of the 21 cm signal from the Epoch of Reionization. Whether or not these experiments deliver a detection of cosmological emission, their limited sensitivity will prevent…

We have extended our previous work to use the Murchison Widefield Array (MWA) as a non-coherent passive radar system in the FM frequency band, using terrestrial FM transmitters to illuminate objects in Low Earth Orbit LEO) and the MWA as…

Instrumentation and Methods for Astrophysics · Physics 2020-12-16 Steve Prabu , Paul J Hancock , Zhang Xiang , Steven J Tingay
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