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The observed hemispherical power asymmetry in cosmic microwave background radiation can be explained by long wavelength mode (long-mode) modulation. In this work we study the prospect of the detection of this effect in the angular power…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-26 Shahram Khosravi , Amirabbas Ghazizadeh , Shant Baghram

The hyperfine 21-cm transition of neutral hydrogen from the early Universe ($z>5$) is a sensitive probe of the formation and evolution of the first luminous sources. Using the Fisher matrix formalism we explore the complex and degenerate…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-24 Sreedhar Balu , Bradley Greig , J. Stuart B. Wyithe

Extracting the neutral hydrogen (HI) signal is a great challenge for cosmological 21cm experiments, both the astrophysical foregrounds and the receiver noise are typically several orders of magnitude greater than the 21cm signal. However,…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-14 Qizhi Huang , Fengquan Wu , Reza Ansari , Xuelei Chen

We perform a Fisher analysis to estimate the expected constraints on the Epoch of Reionization (EoR) model parameters (i.e., minimum virial temperature, the ionizing efficiency and the mean free path of ionizing photons) taking into account…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-04 Hayato Shimabukuro , Shintaro Yoshiura , Keitaro Takahashi , Shuichiro Yokoyama , Kiyotomo Ichiki

The redshifted 21-cm signal from the epoch of reionization (EoR) directly probes the ionization and thermal states of the intergalactic medium during that period. In particular, the distribution of the ionized regions around the radiating…

The 21-cm signal of neutral hydrogen - emitted during the Epoch of Reionization - promises to be an important source of information for the study of the infant universe. However, its detection is impossible without sufficient mitigation of…

Instrumentation and Methods for Astrophysics · Physics 2019-01-09 A. Mouri Sardarabadi , L. V. E. Koopmans

We present new constraints on the 21cm Epoch of Reionization (EoR) power spectrum derived from 3 months of observing with a 32-antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of…

We present the first application of the isosceles bispectrum to MCMC parameter inference from the cosmic 21-cm signal. We extend the MCMC sampler 21cmMC to use the fast bispectrum code, BiFFT, when computing the likelihood. We create mock…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Catherine A. Watkinson , Bradley Greig , Andrei Mesinger

We attempt to measure the $z = 8.2$ Epoch of Reionization (EoR) 21-cm bispectrum (BS) using Murchison Widefield Array (MWA) $154.2~\mathrm{MHz}$ data. We find that $B(k_{1\perp}, k_{2\perp}, k_{3\perp}, k_{1\parallel}, k_{2\parallel})$ the…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Sukhdeep Singh Gill , Somnath Bharadwaj , Khandakar Md Asif Elahi , Shiv K. Sethi , Akash Kumar Patwa

The first measurements of the 21 cm brightness temperature power spectrum from the epoch of reionization will very likely be achieved in the near future by radio interferometric array experiments such as the Hydrogen Epoch of Reionization…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-22 Xiaosheng Zhao , Yi Mao , Benjamin D. Wandelt

The 21-cm anisotropies from the neutral hydrogen distribution prior to the era of reionization is a sensitive probe of primordial non-Gaussianity. Unlike the case with cosmic microwave background, 21-cm anisotropies provide multi-redshift…

Astrophysics · Physics 2009-06-23 Asantha Cooray , Chao Li , Alessandro Melchiorri

Detecting the 21-cm hyperfine transition from neutral hydrogen in the intergalactic medium is our best probe for understanding the astrophysical processes driving the Epoch of Reionisation (EoR). The primary means for a detection of this…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Bradley Greig , Yuan-Sen Ting , Alexander A. Kaurov

During the Epoch of reionisation, the intergalactic medium is reionised by the UV radiation from the first generation of stars and galaxies. One tracer of the process is the 21 cm line of hydrogen that will be observed by the Square…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-29 Julien Hiegel , Emilie Thélie , Dominique Aubert , Jonathan Chardin , Nicolas Gillet , Pierre Galois , Nicolas Mai , Pierre Ocvirk , Rodrigo Ibata

We assess the impact of inhomogeneous reionization on detection of HII regions surrounding luminous high redshift quasars using planned low frequency radio telescopes. Our approach is to implement a semi-numerical scheme to calculate the…

Astrophysics · Physics 2017-07-24 Paul M. Geil , Stuart Wyithe

We analyse the evolution of the largest ionized region using the topological and morphological evolution of the redshifted 21-cm signal coming from the neutral hydrogen distribution during the different stages of reionization. For this…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-12 Saswata Dasgupta , Samit Kumar Pal , Satadru Bag , Sohini Dutta , Suman Majumdar , Abhirup Datta , Aadarsh Pathak , Mohd Kamran , Rajesh Mondal , Prakash Sarkar

This review summarizes recent studies of the cold neutral hydrogen gas associated with galaxies probed via the HI 21-cm absorption line. HI 21-cm absorption against background radio-loud quasars is a powerful tool to study the neutral gas…

Astrophysics of Galaxies · Physics 2019-10-16 Rajeshwari Dutta

We provide measurements of the neutral hydrogen fraction xHI at z~6, by comparing semi-analytical models of the Lyalpha forest with observations of high-z quasars and Gamma Ray Bursts absorption spectra. We analyze the transmitted flux in a…

Astrophysics · Physics 2010-11-11 S. Gallerani , A. Ferrara , X. Fan , Choudhury T. Roy , R. Salvaterra

A detection of the 21-cm signal power spectrum from the Epoch of Reionization is imminent, thanks to consistent advancements from telescopes such as LOFAR, MWA, and HERA, along with the development of SKA. In light of this progress, it is…

We report the first direct detection of the cosmological power spectrum using the intensity signal from 21-cm emission of neutral hydrogen (HI), derived from interferometric observations with the L-band receivers of the new MeerKAT radio…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-31 Sourabh Paul , Mario G. Santos , Zhaoting Chen , Laura Wolz

Intensity mapping of 21-cm line by several radio telescope experiments will probe the large-scale structure of the Universe in the post-reionization epoch. It requires a theoretical framework of neutral hydrogen (HI) clustering, such as…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Rika Ando , Atsushi J Nishizawa , Shimizu Ikkoh , Kentaro Nagamine
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