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The redshifted 21 cm line signal is a powerful probe of the cosmic dawn and the epoch of reionization. The global spectrum can potentially be detected with a single antenna and spectrometer. However, this measurement requires an extremely…

Instrumentation and Methods for Astrophysics · Physics 2024-12-10 Shijie Sun , Eloy de Lera Acedo , Fengquan Wu , Bin Yue , Jiacong Zhu , Xuelei Chen

The Cosmic Dawn was marked by the formation of the first stars, and preceded the Epoch of Reionization (EoR), when the Universe underwent a fundamental transformation caused by the radiation from these first stars and galaxies.…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Oscar Sage David O'Hara , Fred Dulwich , Eloy de Lera Acedo , Jiten Dhandha , Thomas Gessey-Jones , Dominic Anstey , Anastasia Fialkov

We extend 21CMMC, a Monte Carlo Markov Chain sampler of 3D reionisation simulations, to perform parameter estimation directly on 3D light-cones of the cosmic 21cm signal. This brings theoretical analysis closer to the tomographic 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Bradley Greig , Andrei Mesinger

Detection of the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn and the Epoch of Reionization is one of the final frontiers of modern observational cosmology. The inherently faint signal makes it susceptible to…

Instrumentation and Methods for Astrophysics · Physics 2023-03-29 Aishrila Mazumder , Abhirup Datta , Mayuri Sathyanarayana Rao , Arnab Chakraborty , Saurabh Singh , Anshuman Tripathi , Madhurima Choudhury

State-of-the-art simulations of reionisation-era 21-cm signal have limited volumes, generally orders of magnitude smaller than observations. Consequently, the Fourier modes in common between simulation and observation have limited overlap,…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-19 Daniela Breitman , Andrei Mesinger , Steven G. Murray , Anshuman Acharya

Observation of the redshifted 21-cm signal from Cosmic Dawn and Epoch of Reionization is a challenging endeavor in observational cosmology. Presence of orders of magnitude brighter astrophysical foregrounds and various instrumental…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-03 Aishrila Mazumder , Abhirup Datta , Arnab Chakraborty , Suman Majumdar

A successful detection of the cosmological 21-cm signal from intensity mapping experiments (for example, during the Epoch of Reioinization or Cosmic Dawn) is contingent on the suppression of subtle systematic effects in the data. Some of…

Detection of the global redshifted 21-cm signal is an excellent means of deciphering the physical processes during the Dark Ages and subsequent Epoch of Reionization (EoR). However, detection of this faint monopole is challenging due to…

Instrumentation and Methods for Astrophysics · Physics 2015-12-16 Saurabh Singh , Ravi Subrahmanyan , N. Udaya Shankar , A. Raghunathan

In the first paper of this series, we proposed a novel method to probe large-scale intergalactic magnetic fields during the cosmic Dark Ages, using 21-cm tomography. This method relies on the effect of spin alignment of hydrogen atoms in a…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-26 Vera Gluscevic , Tejaswi Venumadhav , Xiao Fang , Christopher Hirata , Antonija Oklopcic , Abhilash Mishra

An active dipole antenna has been designed to measure transient electric field induced by ultra high energy cosmic rays for the CODALEMA experiment. The main requirements for this detector, composed of a low noise preamplifier placed close…

Instrumentation and Methods for Astrophysics · Physics 2015-08-13 Didier Charrier

A redshifted 21 cm line absorption signature is commonly expected from the cosmic dawn era, when the first stars and galaxies formed. The detailed traits of this signal can provide important insight on the cosmic history. However, high…

Instrumentation and Methods for Astrophysics · Physics 2022-04-20 Yuan Shi , Furen Deng , Yidong Xu , Fengquan Wu , Qisen Yan , Xuelei Chen

Separating the cosmological redshifted 21-cm signal from foregrounds is a major challenge. We present the cross-correlation of the redshifted 21-cm emission from neutral hydrogen (HI) in the post-reionization era with the Ly-alpha forest as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Tapomoy Guha Sarkar , Somnath Bharadwaj , Tirthankar Roy Choudhury , Kanan Datta

Upcoming experiments such as Hydrogen Epoch of Reionization Array (HERA) and Square Kilometre Array (SKA) are intended to measure the 21cm signal over a wide range of redshifts, representing an incredible opportunity in advancing our…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Héctor J. Hortúa , Riccardo Volpi , Luigi Malagò

The 21-cm signal from neutral hydrogen is anticipated to reveal critical insights into the formation of early cosmic structures during the Cosmic Dawn and the subsequent Epoch of Reionization. However, the intrinsic faintness of the signal,…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-27 Yuchen Liu , Eloy de Lera Acedo , Peter Sims

In this paper, we propose a novel method to recover the 21cm global signal from the 21cm power spectrum using artificial neural networks (ANNs). The 21cm global signal is crucial for understanding cosmic evolution from the Dark Ages through…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-09 Hayato Shimabukuro

The far side of the Moon, shielded from terrestrial radio frequency interference and beyond the influence of Earth's ionosphere, should offer a uniquely quiet environment for radio astronomy and cosmological experiments. The radio sky below…

Instrumentation and Methods for Astrophysics · Physics 2026-02-26 Kaja M. Rotermund , Aritoki Suzuki , Stuart D. Bale , Anže Slosar

Cosmic Dawn, when the first stars and proto-galaxies began to form, is commonly expected to be accompanied by an absorption signature at radio frequencies. This feature arises as Lyman-$\alpha$ photons emitted by these first luminous…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-15 Peter H. Sims , Jonathan C. Pober

The EDGES collaboration reported the finding of an unexpectedly deep absorption in the radio background at 78 MHz and interpreted the dip as a first detection of redshifted 21-cm from Cosmic Dawn. We have attempted an alternate analysis,…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-31 Saurabh Singh , Ravi Subrahmanyan

Direct detection of the Epoch of Reionization via the redshifted 21-cm line will have unprecedented implications on the study of structure formation in the early Universe. To fulfill this promise current and future 21-cm experiments will…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 F. Mertens , A. Ghosh , L. V. E. Koopmans

The global 21 cm signal from the hyperfine transition of cosmic atomic hydrogen is theorised to track the state of the early Universe via the analysis of its absorption and emission with respect to the radio background. Detecting this…

Instrumentation and Methods for Astrophysics · Physics 2026-02-25 Joe H. N. Pattison , Dominic J. Anstey , Eloy de Lera Acedo
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