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Observations of anisotropies in the brightness temperature of the 21 cm line of neutral hydrogen from the period before reionization would shed light on the dawn of the first stars and galaxies. In this paper, we use large-scale…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-16 M. G. Santos , M. B. Silva , J. R. Pritchard , R. Cen , A. Cooray

Observations of the high-redshift Universe using the 21 cm line of neutral hydrogen and complimentary emission lines from the first galaxies promise to open a new door for our understanding of the epoch of reionization. We present…

Astrophysics of Galaxies · Physics 2019-03-13 Sebastian Dumitru , Girish Kulkarni , Guilaine Lagache , Martin G. Haehnelt

This paper is the first in a series of papers describing the impact of antenna instrumental artefacts on the 21-cm cosmology experiments to be carried out by the low frequency instrument (SKA1-LOW) of the Square Kilometre Array telescope…

Studying the cosmic dawn and the epoch of reionization through the redshifted 21 cm line are among the major science goals of the SKA1. Their significance lies in the fact that they are closely related to the very first stars in the…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-23 T. Roy Choudhury , Kanan Datta , Suman Majumdar , Raghunath Ghara , Aseem Paranjape , Rajesh Mondal , Somnath Bharadwaj , Saumyadip Samui

We investigate whether the redshift evolution of the fixed-$k$ dimensionless 21 cm power spectrum, $\Delta^2_{21}(k, z)$, contains sufficient information to reconstruct reionization histories $x_{\mathrm{HI}}(z)$ with artificial neural…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-21 Yu-Le Wang , Hayato Shimabukuro

High-number-density tracers of large-scale structure, such as the HI-rich galaxies measured by 21 cm intensity mapping, have low sampling noise, making them particularly promising as cosmological probes. At large scales, this sampling noise…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-28 Simon Foreman , Andrej Obuljen , Marko Simonović

Realizing the potential of 21 cm tomography to statistically probe the intergalactic medium before and during the Epoch of Reionization requires large telescopes and precise control of systematics. Next-generation telescopes are now being…

Instrumentation and Methods for Astrophysics · Physics 2016-08-17 Joshua S. Dillon , Aaron R. Parsons

In the most distant reaches of the Universe, the 21-cm hyperfine transition in neutral hydrogen provides one of the only available tracers of large-scale structure. A number of instruments have been working and planned to measure the 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-15 Teppei Minoda , Shohei Saga , Tomo Takahashi , Hiroyuki Tashiro , Daisuke Yamauchi , Shuichiro Yokoyama , Shintaro Yoshiura

Tomographic three-dimensional 21 cm images from the epoch of reionization contain a wealth of information about the reionization of the intergalactic medium by astrophysical sources. Conventional power spectrum analysis cannot exploit the…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-22 Xiaosheng Zhao , Yi Mao , Cheng Cheng , Benjamin D. Wandelt

Detection of individual luminous sources during the reionization epoch and cosmic dawn through their signatures in the HI 21-cm signal is one of the direct approaches to probe the epoch. Here, we summarize our previous works on this and…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-27 Kanan K. Datta , Raghunath Ghara , Suman Majumdar , T. Roy Choudhury , Somnath Bharadwaj , Himadri Roy , Abhirup Datta

The next generation 21 cm surveys open a new window onto the early stages of cosmic structure formation and provide new insights about the Epoch of Reionization (EoR). However, the non-Gaussian nature of the 21 cm signal along with the huge…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-18 Héctor J. Hortúa , Luigi Malago , Riccardo Volpi

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

We present an innovative approach to constraining the non-cold dark matter model using a convolutional neural network (CNN). We perform a suite of hydrodynamic simulations with varying dark matter particle masses and generate mock 21cm…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-23 Koya Murakami , Atsushi J. Nishizawa , Kentaro Nagamine , Ikko Shimizu

We present a method for extracting the expected cosmological 21-cm signal from the epoch of reionization, taking into account contaminating radiations and random instrumental noise. The method is based on the maximum a-posteriori…

Astrophysics · Physics 2008-12-21 Liron Gleser , Adi Nusser , Andrew J. Benson

The Square Kilometre Array (SKA) will be the first low-frequency instrument with the capability to directly image the structures of the Epoch of Reionization (EoR). Indeed, deep imaging of the EoR over 5 targeted fields of 20 square degrees…

Instrumentation and Methods for Astrophysics · Physics 2021-03-31 Qian Zheng , Xiang-Ping Wu , Quan Guo , Melanie Johnston-Hollitt , Huanyuan Shan , Stefan W. Duchesne , Weitian Li

The cross-correlation between the 21 cm emission from the high-redshift intergalactic medium and the near-infrared (NIR) background light from the high-redshift galaxies promises to be a powerful probe of cosmic reionization. In this paper,…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Xiao-Chun Mao

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

Probing the nature of dark matter (DM) remains an outstanding problem in modern cosmology. The 21 cm signal, as a sensitive tracer of neutral hydrogen during cosmic dawn, provides a unique means to investigate DM nature during this critical…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-24 Meng-Lin Zhao , Yue Shao , Sai Wang , Xin Zhang

The 21 cm signal from the Epoch of Reionization will be observed with the up-coming Square Kilometer Array (SKA). SKA should yield a full tomography of the signal which opens the possibility to explore its non-Gaussian properties. How can…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-28 Benoit Semelin , Romain Mériot , Ashutosh Mishra , David Cornu

The SKA will build upon early detections of the EoR by precursor instruments, such as MWA, PAPER, and LOFAR, and planned instruments, such as HERA, to make the first high signal-to-noise measurements of fluctuations in the 21 cm brightness…

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