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Related papers: Exploring the Cosmic Dawn with NenuFAR

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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…

The line of sight direction in the redshifted 21-cm signal coming from the cosmic dawn and the epoch of reionization is quite unique in many ways compared to any other cosmological signal. Different unique effects, such as the evolution…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-28 Suman Majumdar , Kanan K. Datta , Raghunath Ghara , Rajesh Mondal , T. Roy Choudhury , Somnath Bharadwaj , Sk. Saiyad Ali , Abhirup Datta

The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is…

Instrumentation and Methods for Astrophysics · Physics 2018-04-25 Saurabh Singh , Ravi Subrahmanyan , N. Udaya Shankar , Mayuri Sathyanarayana Rao , B. S. Girish , A. Raghunathan , R. Somashekar , K. S. Srivani

The period between the creation of the cosmic microwave background at a redshift of ~1000 and the formation of the first stars and black holes that re-ionize the intergalactic medium at redshifts of 10-20 is currently unobservable. The…

Instrumentation and Methods for Astrophysics · Physics 2016-11-17 Dayton L. Jones , T. Joseph W. Lazio , Jack O. Burns

Understanding the astrophysical nature of the first stars remains an unsolved problem in cosmology. The redshifted global 21-cm signal $({T}_{21})$ acts as a treasure trove to probe the cosmic dawn era -- when the intergalactic medium was…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-16 Vivekanand Mohapatra , Johnny J , Pravin Kumar Natwariya , Jishnu Goswami , Alekha C. Nayak

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

The birth of the first luminous sources and the ensuing epoch of reionization are best studied via the redshifted 21-cm emission line, the signature of the first two imprinting the last. In this work we present a fully-Bayesian method,…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-27 G. Bernardi , J. T. L. Zwart , D. Price , L. J. Greenhill , A. Mesinger , J. Dowell , T. Eftekhari , S. W. Ellingson , J. Kocz , F. Schinzel

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 Experiment to Detect the Global Epoch of Reionization Signature (EDGES) recently reported a strong 21-cm absorption signal relative to the cosmic microwave background at $z \sim 18$. While its anomalous amplitude may indicate new…

Astrophysics of Galaxies · Physics 2018-12-12 Jordan Mirocha , Steven R. Furlanetto

Understanding the formation and evolution of the first stars and galaxies represents one of the most exciting frontiers in astronomy. Since the universe was filled with hydrogen atoms at early times, the most promising probe of the epoch of…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-24 Rennan Barkana

Imaging the Universe during the first hundreds of millions of years remains one of the exciting challenges facing modern cosmology. Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Jonathan R. Pritchard , Abraham Loeb

A recent observation by the EDGES collaboration shows a strong absorption signal in the global 21-cm spectrum from around a redshift of $z = 17$. This absorption is stronger than the maximum prediction by existing models and indicates that…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-11 Suman Chatterjee , Somnath Bharadwaj

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

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

The 21-cm signal holds the key to understanding the first structure formation during cosmic dawn. Theoretical progress over the last decade has focused on simulations of this signal, given the nonlinear and nonlocal relation between initial…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-06 Julian B. Muñoz

The cosmic 21-cm line of hydrogen is expected to be measured in detail by the next generation of radio telescopes. The enormous dataset from future 21-cm surveys will revolutionize our understanding of early cosmic times. We present a…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-11 Sudipta Sikder , Rennan Barkana , Itamar Reis , Anastasia Fialkov

The 21cm line refers to a forbidden transition in neutral hydrogen associated with alignment of spins of the proton and electron. It is a very low energy transition that is emitted whenever there is neutral hydrogen in the Universe. Since…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-12 Adrian Liu , Laura Newburgh , Benjamin Saliwanchik , Anže Slosar

While the origin and composition of dark matter and dark energy remains unknown, it is possible that they might represent two manifestations of a single entity, as occurring in unified dark sector models. On the other hand, advances in our…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-02 Weiqiang Yang , Supriya Pan , Sunny Vagnozzi , Eleonora Di Valentino , David F. Mota , Salvatore Capozziello

There are several planned and ongoing experiments designed to explore the Epoch of Reionization (EoR), the pivotal period during which the gas in the intergalactic medium went from being entirely neutral to almost entirely ionized. These…

Astrophysics of Galaxies · Physics 2010-08-27 Vibor Jelic

Neutral hydrogen pervades the infant Universe, and its redshifted 21-cm signal allows one to chart the Universe. This signal allows one to probe astrophysical processes such as the formation of the first stars, galaxies, (super)massive…