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Related papers: Global 21-cm signal extraction from foreground and…

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The highly redshifted 21 cm line of neutral hydrogen has become recognized as a unique probe of cosmology from relatively low redshifts (z ~ 1) up through the Epoch of Reionization (z ~ 8) and even beyond. To date, most work has focused on…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Jonathan C. Pober

The absorption feature in the global spectrum is likely the first 21 cm observable from the cosmic dawn, which provides valuable insights into the earliest history of structure formation. We run a set of high-resolution hydrodynamic…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-23 Yidong Xu , Bin Yue , Xuelei Chen

The cosmological global (sky-averaged) 21-cm signal is a powerful tool to probe the evolution of the intergalactic medium (IGM) in high-redshift Universe ($z \leq 6$). One of the biggest observational challenges is to remove the foreground…

Instrumentation and Methods for Astrophysics · Physics 2018-11-14 Bang D. Nhan , Richard F. Bradley , Jack O. Burns

Enlightening our understanding of the first galaxies responsible for driving reionisation requires detecting the 21-cm signal from neutral hydrogen. Interpreting the wealth of information embedded in this signal requires Bayesian inference.…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-22 Bradley Greig , David Prelogović , Yuxiang Qin , Yuan-Sen Ting , Andrei Mesinger

We estimate the global signal in the redshifted hyperfine structure line 21 cm of hydrogen atoms formed during the Dark Ages and Cosmic Dawn epochs. The evolution of the brightness temperature in this line was computed to study its…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-11 Bohdan Novosyadlyj , Yurii Kulinich , Danylo Koval

Considerable observational efforts are being dedicated to measuring the sky-averaged (global) 21-cm signal of neutral hydrogen from Cosmic Dawn and the Epoch of Reionization. Deriving observational constraints on the astrophysics of this…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 Christian H. Bye , Stephen K. N. Portillo , Anastasia Fialkov

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

Observations of fluctuations in the redshifted 21 cm radiation from neautral hydrogen (HI) are perceived to be an important future probe of the universe at high redshifts. Under the assumption that at redshifts z less than 6…

Astrophysics · Physics 2009-11-13 Sk. Saiyad Ali , Somnath Bharadwaj , Sanjay K. Pandey

Emulation of the Global (sky-averaged) 21-cm signal with neural networks has been shown to be an essential tool for physical signal modelling. In this paper we present globalemu, a Global 21-cm signal emulator that uses redshift as a…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-18 H. T. J. Bevins , W. J. Handley , A. Fialkov , E. de Lera Acedo , K. Javid

The 21cm global signal is an important probe to reveal the properties of the first astrophysical objects and the processes of the structure formation from which one can constrain astrophysical and cosmological parameters. To extract the…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-22 Shintaro Yoshiura , Teppei Minoda , Tomo Takahashi

The most promising near-term observable of the cosmic dark age prior to widespread reionization (z~15-200) is the sky-averaged \lambda 21 cm background arising from hydrogen in the intergalactic medium. Though an individual antenna could in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 G. Bernardi , M. McQuinn , L. J. Greenhill

Twenty-one centimeter tomography is emerging as a powerful tool to explore the end of the cosmic dark ages and the reionization epoch, but it will only be as good as our ability to accurately model and remove astrophysical foreground…

Astrophysics · Physics 2008-11-26 Xiaomin Wang , Max Tegmark , Mario Santos , Lloyd Knox

The redshifted 21cm line of neutral hydrogen (Hi), potentially observable at low radio frequencies (~50-200 MHz), is a promising probe of the physical conditions of the inter-galactic medium during Cosmic Dawn and the Epoch of Reionisation…

Global (i.e. sky-averaged) $21$~cm signal experiments can measure the evolution of the universe from the Cosmic Dawn to the Epoch of Reionization. These measurements are challenged by the presence of bright foreground emission that can be…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 Marta Spinelli , Gianni Bernardi , Mario G. Santos

We use a large N-body simulation to examine the detectability of HI in emission at redshift z ~ 1, and the constraints imposed by current observations on the neutral hydrogen mass function of galaxies at this epoch. We consider three…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Nishikanta Khandai , Shiv K. Sethi , Tiziana Di Matteo , Rupert A. C. Croft , Volker Springel , Anirban Jana , Jeffrey P. Gardner

Observation of multifrequency angular power spectrum of the redshifted 21-cm brightness temperature fluctuation from the neutral hydrogen holds the key to understand the structure formation and its evolution during the reionization and…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-28 Saikat Gayen , Jais Kumar , Prasun Dutta , Khandakar Md Asif Elahi , Samir Choudhuri , Nirupam Roy

Detection of the \hi~ 21-cm power spectrum is one of the key science drivers of several ongoing and upcoming low-frequency radio interferometers. However, the major challenge in such observations come from bright foregrounds, whose accurate…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-29 Madhurima Choudhury , Abhirup Datta , Suman Majumdar

Direct detection of the Cosmic Dawn and Epoch of Reionization via the redshifted 21-cm line of neutral Hydrogen will have unprecedented implications for studying structure formation in the early Universe. This exciting goal is challenged by…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-26 Florent G. Mertens , Jérôme Bobin , Isabella P. Carucci

The cosmological 21 cm signal is one of the most promising avenues to study the Epoch of Reionization. One class of experiments aiming to detect this signal is global signal experiments measuring the sky-averaged 21 cm brightness…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-19 Stefan Heimersheim , Leiv Rønneberg , Henry Linton , Filippo Pagani , Anastasia Fialkov

Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21 cm line signal. If dark matter (DM) decays or annihilates the corresponding energy input affects the hydrogen kinetic temperature and ionized…

Astrophysics · Physics 2008-11-26 M. Valdes , A. Ferrara , M. Mapelli , E. Ripamonti