Probing early Universe through redshifted 21-cm signal: Modeling and observational challenges

AK Shaw, A Chakraborty, M Kamran, R Ghara… - Journal of Astrophysics …, 2023 - Springer
Cosmic dawn (CD) and the epoch of reionization (EoR) are the most important parts of
cosmic history during which the first luminous structures emerged. These first objects heated …

First upper limits on the 21 cm signal power spectrum from cosmic dawn from one night of observations with NenuFAR

S Munshi, FG Mertens, LVE Koopmans… - Astronomy & …, 2024 - aanda.org
The redshifted 21 cm signal from neutral hydrogen is a direct probe of the physics of the
early universe and has been an important science driver of many present and upcoming …

On the use of temporal filtering for mitigating galactic synchrotron calibration bias in 21 cm reionization observations

N Charles, N Kern, G Bernardi, L Bester… - Monthly Notices of …, 2023 - academic.oup.com
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 …

Diffuse sources, clustering, and the excess anisotropy of the radio synchrotron background

FJ Cowie, AR Offringa, BK Gehlot… - Monthly Notices of …, 2023 - academic.oup.com
We present the largest low frequency (120 MHz) arcminute resolution image of the radio
synchrotron background (RSB) to date, and its corresponding angular power spectrum of …

Validation of the HERA Phase I epoch of reionization 21 cm power spectrum software pipeline

JE Aguirre, SG Murray, R Pascua… - The Astrophysical …, 2022 - iopscience.iop.org
We describe the validation of the HERA Phase I software pipeline by a series of modular
tests, building up to an end-to-end simulation. The philosophy of this approach is to validate …

Assessing the impact of two independent direction-dependent calibration algorithms on the LOFAR 21 cm signal power spectrum-And applications to an observation …

H Gan, FG Mertens, LVE Koopmans… - Astronomy & …, 2023 - aanda.org
Context. Detecting the 21 cm signal from the epoch of reionisation (EoR) has been highly
challenging due to the strong astrophysical foregrounds, ionospheric effects, radio …

Ionospheric contributions to the excess power in high-redshift 21-cm power-spectrum observations with LOFAR

SA Brackenhoff, M Mevius… - Monthly Notices of …, 2024 - academic.oup.com
The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of
temporal and spatial scales. When an interferometer is not sufficiently calibrated for the …

Spectral redundancy for calibrating interferometers and suppressing the foreground wedge in 21 cm cosmology

TA Cox, AR Parsons, JS Dillon… - Monthly Notices of …, 2024 - academic.oup.com
Observations of 21 cm line from neutral hydrogen promise to be an exciting new probe of
astrophysics and cosmology during the Cosmic Dawn and through the Epoch of …

Redshifted 21-cm bispectrum: impact of the source models on the signal and the IGM physics from the Cosmic Dawn

M Kamran, R Ghara, S Majumdar… - … of Cosmology and …, 2022 - iopscience.iop.org
The emissions from the first luminous sources drive the fluctuations in the 21-cm signal at
Cosmic Dawn (CD) via two main astrophysical processes, namely Lyα coupling and X-ray …

Evidence of Ultrafaint Radio Frequency Interference in Deep 21 cm Epoch of Reionization Power Spectra with the Murchison Wide-field Array

MJ Wilensky, MF Morales, BJ Hazelton… - The Astrophysical …, 2023 - iopscience.iop.org
We present deep upper limits from the 2014 Murchison Widefield Array Phase I observing
season, with a particular emphasis on identifying the spectral fingerprints of extremely faint …