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A number of experiments are set to measure the 21-cm signal of neutral hydrogen from the Epoch of Reionization (EoR). The common denominator of these experiments are the large data sets produced, contaminated by various instrumental…

The detection of the Epoch of Reionization (EoR) delay power spectrum using a "foreground avoidance method" highly depends on the instrument chromaticity. The systematic effects induced by the radio-telescope spread the foreground signal in…

Observation of multifrequency angular power spectrum of the redshifted 21-cm brightness temperature fluctuation from the neutral hydrogen holds the key to understand the structure formation and its evolution during the reionization and…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-28 Saikat Gayen , Jais Kumar , Prasun Dutta , Khandakar Md Asif Elahi , Samir Choudhuri , Nirupam Roy

The EoR 21-cm signal is expected to become highly non-Gaussian as reionization progresses. This severely affects the error-covariance of the EoR 21-cm power spectrum which is important for predicting the prospects of a detection with…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-14 Rajesh Mondal , Somnath Bharadwaj , Suman Majumdar

Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract the cosmological signal (CS) from…

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…

One of the aims of the Low Frequency Array (LOFAR) Epoch of Reionization (EoR) project is to measure the power spectrum of variations in the intensity of redshifted 21-cm radiation from the EoR. The sensitivity with which this power…

Neutral hydrogen (HI) serves as a crucial probe for the Cosmic Dawn and the Epoch of Reionization (EoR). Actual observations of the 21-cm signal often encounter challenges such as thermal noise and various systematic effects. To overcome…

We report the first upper limits on the power spectrum of 21-cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Array (HERA) experiment. HERA Phase II constitutes several…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-27 The HERA Collaboration , Zuhra Abdurashidova , Tyrone Adams , James E. Aguirre , Rushelle Baartman , Rennan Barkana , Lindsay M. Berkhout , Gianni Bernardi , Tashalee S. Billings , Bruno B. Bizarria , Judd D. Bowman , Daniela Breitman , Philip Bull , Jacob Burba , Ruby Byrne , Steven Carey , Rajorshi Sushovan Chandra , Kai-Feng Chen , Samir Choudhuri , Tyler Cox , David R. DeBoer , Eloy de Lera Acedo , Matt Dexter , Jiten Dhandha , Joshua S. Dillon , Scott Dynes , Nico Eksteen , John Ely , Aaron Ewall-Wice , Nicolas Fagnoni , Anastasia Fialkov , Steven R. Furlanetto , Kingsley Gale-Sides , Hugh Garsden , Adelie Gorce , Deepthi Gorthi , Ziyaad Halday , Bryna J. Hazelton , Jacqueline N. Hewitt , Jack Hickish , Tian Huang , Daniel C. Jacobs , Alec Josaitis , Nicholas S. Kern , Joshua Kerrigan , Piyanat Kittiwisit , Matthew Kolopanis , Adam Lanman , Paul La Plante , Adrian Liu , Yin-Zhe Ma , David H. E. MacMahon , Lourence Malan , Cresshim Malgas , Keith Malgas , Bradley Marero , Zachary E. Martinot , Lisa McBride , Andrei Mesinger , Jordan Mirocha , Nicel Mohamed-Hinds , Mathakane Molewa , Miguel F. Morales , Julian B. Muñoz , Steven G. Murray , Bojan Nikolic , Hans Nuwegeld , Aaron R. Parsons , Robert Pascua , Nipanjana Patra , Simon Pochinda , Yuxiang Qin , Eleanor Rath , Nima Razavi-Ghods , Daniel Riley , Kathryn Rosie , Mario G. Santos , Saurabh Singh , Dara Storer , Hilton Swarts , Jianrong Tan , Emilie Thélie , Pieter van Wyngaarden , Michael J. Wilensky , Peter K. G. Williams , Haoxuan Zheng

Several experimental efforts are underway to measure the power spectrum of 21cm fluctuations from the Epoch of Reionization (EoR) using low-frequency radio interferometers. Experiments like the Hydrogen Epoch of Reionization Array (HERA)…

Instrumentation and Methods for Astrophysics · Physics 2019-06-19 Adam E. Lanman , Jonathan C. Pober

The epoch of reionization power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints on the physics of reionization. The primary obstacle to the…

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 high dynamic range between contaminating foreground emission and the fluctuating 21cm brightness temperature field is one of the most problematic characteristics of 21cm intensity mapping data. While these components would ordinarily…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-13 Melis O. Irfan , Philip Bull

The non-Gaussian nature of the epoch of reionization (EoR) 21-cm signal has a significant impact on the error variance of its power spectrum $P({\bf \textit{k}})$. We have used a large ensemble of semi-numerical simulations and an…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-26 Rajesh Mondal , Somnath Bharadwaj , Suman Majumdar

Cross-correlating 21cm and Ly$\alpha$ intensity maps of the Epoch of Reionization (EoR) promises to be a powerful tool for exploring the properties of the first galaxies. Next-generation intensity mapping experiments such as the Hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-02 Tyler A. Cox , Daniel C. Jacobs , Steven G. Murray

Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process. In a delay-based analysis, the mapping between instrumental and cosmological space is not a one-to-one relation.…

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…

The Epoch of Reionization (EoR)---when neutral hydrogen in the intergalactic medium was systematically ionized---is a period in our Universe's history that is currently poorly understood. However, a key prediction of most models is a…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-25 Michael Pagano , Adrian Liu

Characterizing the epoch of reionization (EoR) at $z\gtrsim 6$ via the redshifted 21 cm line of neutral Hydrogen (HI) is critical to modern astrophysics and cosmology, and thus a key science goal of many current and planned low-frequency…