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This work presents an analytical approach for studying the cosmological 21cm background signal from the Dark Ages (DA) and subsequent Epoch of Reionization (EoR). We simulate differential observations of a galaxy cluster to demonstrate how…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-22 Charles Mpho Takalana , Paolo Marchegiani , Geoff Beck , Sergio Colafrancesco

Foreground emission makes it difficult to detect the highly-redshifted cosmological 21 cm signal at any frequency. However, at low frequencies foregrounds are likely to become optically thick, which would make it completely impossible to…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 Daniya Seitova , Jonathan C. Pober

We study the detectability of the cross-correlation between 21 cm emission from the intergalactic medium and the galaxy distribution during (and before) reionization. We show that first-generation 21 cm experiments, such as the Mileura…

Astrophysics · Physics 2009-11-11 Steven Furlanetto , Adam Lidz

Recent simulations show the Epoch of Reionization (EoR) 21-cm signal to be inherently non-Gaussian whereby the error covariance matrix $\mathbf{C}_{ij}$ of the 21-cm power spectrum (PS) contains a trispectrum contribution that would be…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-01 Abinash Kumar Shaw , Somnath Bharadwaj , Rajesh Mondal

Intensity mapping of multiple emission lines is emerging as a new branch to astronomy, to probe both properties of ionizing sources and the medium between, in particular the intergalactic medium. For Epoch of Reionization (EoR) studies,…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-03 Caroline Heneka , Asantha Cooray

We study the spherically averaged bispectrum of the 21-cm signal from the Epoch of Reionization (EoR). This metric provides a quantitative measurement of the level of non-Gaussianity of the signal which is expected to be high. We focus on…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-22 Rajesh Mondal , Garrelt Mellema , Abinash Kumar Shaw , Mohd Kamran , Suman Majumdar

Measurement of the spatial distribution of neutral hydrogen via the redshifted 21 cm line promises to revolutionize our knowledge of the epoch of reionization and the first galaxies, and may provide a powerful new tool for observational…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Miguel F. Morales , J. Stuart B. Wyithe

The epoch of reionization (EoR), marking the Universe's transition from a neutral to ionized state, represents a pivotal phase for understanding the formation of the first stars and galaxies. Intensity mapping of atomic and molecular lines,…

Astrophysics of Galaxies · Physics 2025-12-17 Anirban Roy , Anthony Pullen , Patrick C. Breysse , Rachel S. Somerville

The Universe's Cosmic Dawn (CD) and Epoch of Reionization (EoR) can be studied using a number of observational probes that provide complementary or corroborating information. Each of these probes suffers from its own systematic and…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-20 Vibor Jelic , Benedetta Ciardi , Elizabeth Fernandez , Hiroyuki Tashiro , Dijana Vrbanec

Telescopes aiming to measure 21cm emission from the Epoch of Reionization must toe a careful line, balancing the need for raw sensitivity against the stringent calibration requirements for removing bright foregrounds. It is unclear what the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Aaron Parsons , Jonathan Pober , Matthew McQuinn , Daniel Jacobs , James Aguirre

We investigate a number of potential foregrounds for an ambitious goal of future radio telescopes such as the Square Kilometer Array (SKA) and Low Frequency Array (LOFAR): spatial tomography of neutral gas at high redshift in 21cm emission.…

Astrophysics · Physics 2009-11-07 S. Peng Oh , Katherine J. Mack

We study the prospects for extracting cosmological and astrophysical parameters from the low radio frequency 21-cm background due to the spin-flip transition of neutral Hydrogen during and prior to the reionization of the Universe. We make…

Astrophysics · Physics 2009-11-11 Mario G. Santos , Asantha Cooray

Isocurvature perturbations expected from multi-field inflation models can leave unique signatures in the early Universe, but remain weakly constrained, especially on small scales. In this work, we investigate the constraining power of…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-19 Zhenfei Qin , Hayato Shimabukuro

The 21-cm global signal is obscured by very bright galactic and extra galactic foreground emissions. Typical single-spectrum fit (SSF) based methods for foreground/signal separation can result in biased estimates of the cosmological signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-27 Yordan D. Ignatov , Jonathan R. Pritchard

Unaccounted for systematics from foregrounds and instruments can severely limit the sensitivity of current experiments from detecting redshifted 21~cm signals from the Epoch of Reionization (EoR). Upcoming experiments are faced with a…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-06 Nithyanandan Thyagarajan , Aaron Parsons , David DeBoer , Judd Bowman , Aaron Ewall-Wice , Abraham Neben , Nipanjana Patra

Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early universe. We assess the impact of instrumental effects on measurements made with the Hydrogen Epoch of…

21cm intensity mapping experiments aim to observe the diffuse neutral hydrogen (HI) distribution on large scales which traces the Cosmic structure. The Square Kilometre Array (SKA) will have the capacity to measure the 21cm signal over a…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-19 Laura Wolz , Filipe B. Abdalla , David Alonso , Chris Blake , Philip Bull , Tzu-Ching Chang , Pedro G. Ferreira , Cheng-Yu Kuo , Marios G. Santos , Richard Shaw

[ABRIDGED] The cosmological 21cm signal is set to become the most powerful probe of the early Universe, with first generation interferometers aiming to make statistical detections of reionization. There is increasing interest also in the…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-08 Andrei Mesinger , Aaron Ewall-Wice , Jacqueline Hewitt

We present a realistic simulation of an SKA-Low cosmic dawn/epoch of reionisation (CD/EoR) observation, which can be used to further the development of foreground-mitigation approaches. The simulation corresponds to a deep (1000 h)…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-18 Anna Bonaldi , Philippa Hartley , Simon Purser , Omkar Bait , Eunseong Lee , Robert Braun , Florent Mertens , Andrea Bracco , Wendy Williams , Cath Trott

The Largest Cluster Statistics\,(LCS) analysis of the redshifted 21\,cm maps has been demonstrated to be an efficient and robust method for following the time evolution of the largest ionized regions\,(LIRs) during the Epoch of…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 Samit Kumar Pal , Saswata Dasgupta , Abhirup Datta , Suman Majumdar , Satadru Bag , Prakash Sarkar