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One key challenge in detecting 21 cm cosmological signal at z > 6 is to separate the cosmological signal from foreground emission. This can be studied in a power spectrum space where the foreground is confined to low delay modes whereas the…

We develop an effective perturbation theory (and, equivalently, a bias expansion) for the inhomogeneous 21cm radiation field from reionization. Using large-scale simulations of cosmological reionization, we find that this expansion…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-20 Matthew McQuinn , Anson D'Aloisio

Line intensity mapping opens up a new and exciting window for probing cosmology and fundamental physics during the Epoch of Reionisation, extending to redshifts previously untested by galaxy surveys. The power spectra of these line…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-21 C. Heneka , L. Amendola

In this chapter, the use of machine learning (ML) in redshifted 21 cm cosmology is discussed, especially for the cosmic dawn, the Epoch of Reionization, and the scientific program of SKA-Low. The 21 cm signal is useful because it can…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-18 Hayato Shimabukuro

A limiting systematic effect in 21-cm interferometric experiments is the chromaticity due to the coupling between the sky and the instrument. This coupling is sourced by the instrument primary beam; therefore it is important to know the…

Instrumentation and Methods for Astrophysics · Physics 2022-06-22 Ainulnabilah Nasirudin , David Prelogovic , Steven G. Murray , Andrei Mesinger , Gianni Bernardi

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…

Predictions for the ability of 21-cm interferometric experiments to discriminate Epoch of Reionization (EoR) signal models are typically limited by the simplicity of data models, whereby foreground signals and characteristics of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Ainulnabilah Nasirudin , Steven Murray , Cathryn Trott , Bradley Greig , Ronniy Joseph , Chris Power

We model a 21 cm intensity mapping survey in the redshift range 0.01<z<1.5 designed to simulate the skies as seen by future radio telescopes such as the Square Kilometre Array (SKA), including instrumental noise and Galactic foregrounds. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-27 L. Wolz , F. B. Abdalla , C. Blake , J. R. Shaw , E. Chapman , S. Rawlings

The 21 cm signal arising from fluctuations in the neutral hydrogen field, and its cross-correlation with other tracers of cosmic density, are promising probes of the high-redshift Universe. In this study, we assess the potential of the 21…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Barun Maity

A near-future detection of the 21cm signal from the epoch of reionization will provide unique opportunities to probe the underlying cosmology, provided that such cosmological information can be extracted with precision. To this end, we…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-28 Wenzer Qin , Katelin Schutz , Aaron Smith , Enrico Garaldi , Rahul Kannan , Tracy R. Slatyer , Mark Vogelsberger

With the first phase of the Square Kilometre Array (SKA1) entering into its final pre-construction phase, we investigate how best to maximise its scientific return. Specifically, we focus on the statistical measurement of the 21 cm power…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-14 Bradley Greig , Andrei Mesinger , Léon V. E. Koopmans

Observations of the high-redshift Universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. Here we review the physics of the 21 cm transition,…

Astrophysics · Physics 2009-11-11 Steven Furlanetto , S. Peng Oh , Frank Briggs

We study the behavior of internal signal chain reflections and antenna cross coupling as systematics for 21 cm cosmological surveys. We outline the mathematics for how these systematics appear in interferometric visibilities and describe…

Instrumentation and Methods for Astrophysics · Physics 2019-10-28 Nicholas S. Kern , Aaron R. Parsons , Joshua S. Dillon , Adam E. Lanman , Nicolas Fagnoni , Eloy de Lera Acedo

One of the most promising ways to study the epoch of reionization (EoR) is through radio observations of the redshifted 21-cm line emission from neutral hydrogen. These observations are complicated by the fact that the mapping of redshifts…

There are several planned and ongoing experiments designed to explore the Epoch of Reionization (EoR), the pivotal period during which the gas in the intergalactic medium went from being entirely neutral to almost entirely ionized. These…

Astrophysics of Galaxies · Physics 2010-08-27 Vibor Jelic

The redshifted 21-cm radiation from the atomic hydrogen (HI) provides an excellent direct probe to study the evolution of HI in IGM and thus reveal the nature of the first luminous objects, their evolution and role during Cosmic Dawn (CD)…

The redshifted 21-cm signal is a unique probe of the early universe, particularly the Epoch of Reionization (EoR). While the 21-cm power spectrum has been the primary statistic for parameter inference, it fails to capture the non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-03 Anoop Krishna , Deepthi Moorkanat , Hiten , Rajesh Mondal

The cosmic 21-cm line of hydrogen is expected to be measured in detail by the next generation of radio telescopes. The enormous dataset from future 21-cm surveys will revolutionize our understanding of early cosmic times. We present a…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-11 Sudipta Sikder , Rennan Barkana , Itamar Reis , Anastasia Fialkov

New low frequency radio telescopes currently being built open up the possibility of observing the 21-cm radiation before the Epoch of Reionization in the future, in particular at redshifts 200 > z > 30, also known as the dark ages. At these…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-03 Rishi Khatri , Benjamin D. Wandelt

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