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Related papers: Peering into the Dark (Ages) with Low-Frequency Sp…

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A measurement of the cosmological 21 cm signal remains a promising but as-of-yet unattained ambition of radio astronomy. A positive detection would provide direct observations of key unexplored epochs of our cosmic history, including the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-18 Morgan Presley , Adrian Liu , Aaron Parsons

It is thought that the Universe went through an early period known as the Dark Ages, during which primeval density fluctuations grew to form the first luminous objects, marking the beginning of Cosmic Dawn around 100 million years after the…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-16 Hyunbae Park , Rennan Barkana , Naoki Yoshida , Sudipta Sikder , Rajesh Mondal , Anastasia Fialkov

The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jordan Mirocha , Geraint J. A. Harker , Jack O. Burns

The Dark Ages (DA) provides a crucial window into the physics of the infant Universe, with the 21-cm signal offering the only direct probe for mapping out the three-dimensional distribution of matter at this epoch. To measure this…

The light of the first astrophysical objects is expected to leave an imprint on the global 21-cm signal as it heats, excites, and ionizes neutral hydrogen. This dependence on early astrophysics introduces significant uncertainties in…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-06 Omer Zvi Katz

The exploration of the Cosmic Dawn, the period of the Universe during which the first stars and galaxies were formed, is one of the last frontiers of modern astronomy and cosmology. The redshifted 21-cm line emission from neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-22 F. G. Mertens , B. Semelin , L. V. E. Koopmans

Empirical studies of the first generation of stars and quasars will likely become feasible within the next decade in several different wavelength bands. Microwave anisotropy experiments, such as MAP or Planck, will set constraints on the…

Astrophysics · Physics 2017-02-08 Zoltan Haiman

Observations of the 21-cm line from primordial hydrogen promise to be one of the best tools to study the early epochs of the Universe: the Dark Ages, the Cosmic Dawn, and the subsequent Epoch of Reionization. In 2018, the EDGES experiment…

Low-frequency observatories are currently being constructed with the goal of detecting redshifted 21cm emission from the epoch of reionization. These observatories will also be able to detect intensity fluctuations in the cumulative 21cm…

Astrophysics · Physics 2015-05-13 Stuart Wyithe , Abraham Loeb , Paul Geil

Detection of the global HI 21 cm signal from Cosmic Dawn and Epoch of Reionization is the key science driver for several ongoing ground-based and future ground/space-based experiments. The crucial spectral features in the global 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-11 Abhirup Datta , Richard Bradley , Jack O. Burns , Geraint Harker , Attila Komjathy , T. Joseph W. Lazio

We discuss low frequency radio astronomy from the moon, predominantly in the context of studying the neutral intergalactic medium during cosmic reionization using the HI 21cm line of neutral hydrogen. The epoch of reionization is the next…

Astrophysics · Physics 2007-05-23 C. L. Carilli , J. N. Hewitt , A. Loeb

The redshifted 21 cm line, arising from neutral hydrogen, offers a unique probe into the intergalactic medium and the first stars and galaxies formed in the early universe. However, detecting this signal is a challenging task because of…

Instrumentation and Methods for Astrophysics · Physics 2025-10-09 Shijie Sun , Jiaqin Xu , Minquan Zhou , Shenzhe Xu , Fengquan Wu , Haoran Zhang , Juyong Zhang , Bin Ma , Zhaohui Shang , Xuelei Chen

Black holes are unique among astrophysical sources: they are the simplest macroscopic objects in the Universe, and they are extraordinary in terms of their ability to convert energy into electromagnetic and gravitational radiation. Our…

Measurements of 21cm intensity mapping (IM) during the dark ages can potentially provide us with an unprecedented window on high redshifts and small scales. One of the main advantages this can bring involves the possibility to probe the…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-06 Eleonora Vanzan , Alvise Raccanelli , Nicola Bartolo

Detecting the redshifted global 21-cm signal from the cosmic dawn (CD) remains a major challenge due to strong terrestrial Radio Frequency Interference (RFI), particularly dominated by Frequency Modulation (FM) transmissions in the 88-110…

Instrumentation and Methods for Astrophysics · Physics 2026-05-22 Yogen Pranesh , Mayuri Sathyanarayana Rao , Saurabh Singh

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

Low-frequency radio observations of neutral hydrogen during and before the epoch of cosmic reionization will provide hundreds of quasi-independent source planes, each of precisely known redshift, if a resolution of ~ 1 arcminutes or better…

Astrophysics · Physics 2010-11-11 R. Benton Metcalf

The cosmic Dark Ages represent a pivotal epoch in the evolution of the Universe, marked by the emergence of the first cosmic structures under the influence of dark matter. The 21-cm hydrogen line, emanating from the hyperfine transition of…

Instrumentation and Methods for Astrophysics · Physics 2024-12-19 Kaan Artuc , Eloy de Lera Acedo

We are approaching a new era to probe the 21-cm neutral hydrogen signal from the period of cosmic dawn. This signal offers a unique window to the virgin Universe, e.g., to study dark matter models with different small-scale behaviours. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-21 Venno Vipp , Andi Hektor , Gert Hütsi

The distribution of matter fluctuations in our universe is key for understanding the nature of dark matter and the physics of the early cosmos. Different observables have been able to map this distribution at large scales, corresponding to…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-01 Julian B. Muñoz , Cora Dvorkin , Francis-Yan Cyr-Racine