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Related papers: Will point sources spoil 21 cm tomography?

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Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

The neutral hydrogen 21cm line is potentially a very powerful probe of the observable universe, and a number of on-going experiments are trying to detect it at cosmological distances. However, the presence of strong foreground radiations…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-14 Qizhi Huang , Fengquan Wu , Xuelei Chen

Studies of the cosmic dark ages ($30 \lesssim z \lesssim 150$) using the highly redshifted 21 cm line of neutral hydrogen offer unparalleled amounts of cosmological information, and recent years have seen the refinement of concepts for such…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-01 Jonathan C. Pober , Willow Smith

Predictions for the ability of 21-cm interferometric experiments to discriminate Epoch of Reionization (EoR) signal models are typically limited by the simplicity of data models, whereby foreground signals and characteristics of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Ainulnabilah Nasirudin , Steven Murray , Cathryn Trott , Bradley Greig , Ronniy Joseph , Chris Power

The measurements of the 21-cm brightness temperature fluctuations from the neutral hydrogen at the Epoch of Reionization (EoR) should inaugurate the next generation of cosmological observables. In this respect, many works have concentrated…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-10 Sebastien Clesse , Laura Lopez-Honorez , Christophe Ringeval , Hiroyuki Tashiro , Michel H. G. Tytgat

The HI 21cm global signal from the Cosmic Dawn and the Epoch of Reionization (EoR) offers critical insights into the evolution of our Universe. Yet, its detection presents significant challenges due to its extremely low…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-09 Yue Wang , Xin Wang , Shijie Sun , Fengquan Wu , Shoudong Luo , 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

This paper deals with the detection problem of extragalactic point-sources in multi-frequency, microwave sky maps that will be obtainable in future cosmic microwave background radiation (CMB) experiments with instruments capable of very…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 R. Vio , P. Andreani , E. P. R. G. Ramos , A. da Silva

The precise measurement of the sky-averaged HI absorption signal between 50 and 200 MHz is the primary goal of global 21-cm cosmology. This measurement has the potential to unravel the underlying physics of cosmic structure formation and…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Emma Shen , Dominic Anstey , Marta Spinelli , Eloy de Lera Acedo , Anastasia Fialkov

When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made…

Redshifted H{\sc\,i} 21 cm emission from unresolved low-redshift large scale structure is a promising window for ground-based Baryon Acoustic Oscillations (BAO) observations. A major challenge for this method is separating the cosmic signal…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Hee-Jong Seo , Christopher M. Hirata

We propose a novel method for the extraction of unresolved point sources from CMB maps. This method is based on the analysis of the phase distribution of the Fourier components for the observed signal and unlike most other methods of…

Astrophysics · Physics 2009-10-31 P. Naselsky , D. Novikov , Joseph Silk

We present a multifrequency approach which optimizes the constraints on cosmological parameters with respect to extragalactic sources and secondary anisotropies contamination on small scales. We model with a minimal number of parameters the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 D. Paoletti , N. Aghanim , M. Douspis , F. Finelli , G. De Zotti , G. Lagache , Aurélie Pénin

The redshifted 21 cm line of neutral hydrogen is a promising probe of the Epoch of Reionization (EoR). However, its detection requires a thorough understanding and control of the systematic errors. We study two systematic biases observed in…

The precise form of the foregrounds for sky-averaged measurements of the 21-cm line during and before the epoch of reionization is unknown. We suggest that the level of complexity in the foreground models used to fit global 21-cm data…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-26 Geraint Harker

One of the critical challenges facing imaging studies of the 21-cm signal at the Epoch of Reionization (EoR) is the separation of astrophysical foreground contamination. These foregrounds are known to lie in a wedge-shaped region of…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-27 Samuel Gagnon-Hartman , Yue Cui , Jacob Kennedy , Adrian Liu , Siamak Ravanbakhsh

[Abridged] The spatially averaged global spectrum of the redshifted 21cm line has generated much experimental interest, for it is potentially a direct probe of the Epoch of Reionization and the Dark Ages. Since the cosmological signal here…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 Adrian Liu , Jonathan R. Pritchard , Max Tegmark , Abraham Loeb

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

Extracting the neutral hydrogen (HI) signal is a great challenge for cosmological 21cm experiments, both the astrophysical foregrounds and the receiver noise are typically several orders of magnitude greater than the 21cm signal. However,…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-14 Qizhi Huang , Fengquan Wu , Reza Ansari , Xuelei Chen

The 21-cm forest is a promising probe of the Epoch of Reionization. The local state of the intergalactic medium (IGM) is encoded in the spectrum of a background source (radio-loud quasars or gamma ray burst afterglow) by absorption at the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Benoit Semelin