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The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of the antenna used to make the observation coupling to the spectral inhomogeneity of these foregrounds. We…

Instrumentation and Methods for Astrophysics · Physics 2021-11-12 Dominic Anstey , Eloy de Lera Acedo , Will Handley

The precise form of the foregrounds for sky-averaged measurements of the 21-cm line during and before the epoch of reionization is unknown. We suggest that the level of complexity in the foreground models used to fit global 21-cm data…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-26 Geraint Harker

We present a comprehensive simulation-based study of the BayesEoR code for 21 cm power spectrum recovery when analytically marginalizing over foreground parameters. To account for covariance between the 21 cm signal and contaminating…

Instrumentation and Methods for Astrophysics · Physics 2023-02-09 Jacob Burba , Peter H. Sims , Jonathan C. Pober

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-04 Mayuri Sathyanarayana Rao , Ravi Subrahmanyan , N Udaya Shankar , Jens Chluba

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

We present a differentiable, end-to-end Bayesian forward modeling framework for line intensity mapping cosmology experiments, with a specific focus on low-frequency radio telescopes targeting the redshifted 21 cm line from neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Nicholas Kern

Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

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

The precise measurement of the sky-averaged HI absorption signal between 50 and 200 MHz is the primary goal of global 21-cm cosmology. This measurement has the potential to unravel the underlying physics of cosmic structure formation and…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Emma Shen , Dominic Anstey , Marta Spinelli , Eloy de Lera Acedo , Anastasia Fialkov

The birth of the first luminous sources and the ensuing epoch of reionization are best studied via the redshifted 21-cm emission line, the signature of the first two imprinting the last. In this work we present a fully-Bayesian method,…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-27 G. Bernardi , J. T. L. Zwart , D. Price , L. J. Greenhill , A. Mesinger , J. Dowell , T. Eftekhari , S. W. Ellingson , J. Kocz , F. Schinzel

We present new observations with the Precision Array for Probing the Epoch of Reionization (PAPER) with the aim of measuring the properties of foreground emission for 21cm Epoch of Reionization experiments at 150 MHz. We focus on the…

Global (i.e. sky-averaged) $21$~cm signal experiments can measure the evolution of the universe from the Cosmic Dawn to the Epoch of Reionization. These measurements are challenged by the presence of bright foreground emission that can be…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 Marta Spinelli , Gianni Bernardi , Mario G. Santos

A critical challenge in measuring the power spectrum of 21cm emission from cosmic reionization is compensating for the frequency dependence of an interferometer's sampling pattern, which can cause smooth-spectrum foregrounds to appear…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 Aaron R. Parsons , Jonathan C. Pober , James E. Aguirre , Christopher L. Carilli , Daniel C. Jacobs , David F. Moore

Power spectrum estimators are an important tool in efforts to detect the 21 cm brightness temperature fluctuations from neutral hydrogen at early times. An initial detection will likely be statistical in nature, meaning that it will not be…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-24 Jacob Burba , Philip Bull , Michael J. Wilensky , Fraser Kennedy , Hugh Garsden , Katrine A. Glasscock

The observations of the redshifted 21-cm signal from neutral hydrogen are a promising probe for understanding the Cosmic Dawn and the Epoch of Reionisation (EoR). One of the primary obstacles to the statistical detection of the Cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-22 Eeshan Beohar , Abhirup Datta , Anshuman Tripathi , Samit Kumar Pal , Rashmi Sagar

The extraction of the sky-averaged 21 cm signal from Cosmic Dawn and the Epoch of Reionization faces significant challenges. The bright and anisotropic Galactic foreground, which is 4 - 5 orders of magnitude brighter than the 21 cm signal,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-10 Haoran Li , Furen Deng , Meng Zhou , Yidong Xu , Xuelei Chen

In order to study the "Cosmic Dawn" and the Epoch of Reionization with 21 cm tomography, we need to statistically separate the cosmological signal from foregrounds known to be orders of magnitude brighter. Over the last few years, we have…

Observations of the EoR with the 21-cm hyperfine emission of neutral hydrogen (HI) promise to open an entirely new window onto the formation of the first stars, galaxies and accreting black holes. In order to characterize the weak 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Abhik Ghosh , L. V. E. Koopmans , Emma Chapman , Vibor Jelic

Detecting and characterizing the Epoch of Reionization and Cosmic Dawn via the redshifted 21-cm hyperfine line of neutral hydrogen will revolutionize the study of the formation of the first stars, galaxies, black holes and intergalactic gas…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 F. G. Mertens , A. Ghosh , L. V. E. Koopmans

The 21 cm signal from cosmic hydrogen is one of the most propitious probes of the early Universe. The detection of this signal would reveal key information about the first stars, the nature of dark matter, and early structure formation. We…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-07 Joe H. N. Pattison , Dominic J. Anstey , Eloy de Lera Acedo
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