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After reionisation, the 21cm emission line of neutral hydrogen within galaxies provides a tracer of dark matter. Next-generation intensity mapping surveys, with the SKA and other radio telescopes, will cover large sky areas and a wide range…

宇宙学与河外天体物理 · 物理学 2022-02-07 Dionysios Karagiannis , José Fonseca , Roy Maartens , Stefano Camera

We introduce a new Bayesian HI spectral line fitting technique capable of obtaining spectroscopic redshifts for millions of galaxies in radio surveys with the Square Kilometere Array (SKA). This technique is especially well-suited to the…

宇宙学与河外天体物理 · 物理学 2017-04-28 Ian Harrison , Michelle Lochner , Michael L. Brown

One approach to extracting the global 21-cm signal from total-power measurements at low radio frequencies is to parametrize the different contributions to the data and then fit for these parameters. We examine parametrizations of the 21-cm…

宇宙学与河外天体物理 · 物理学 2015-12-04 Geraint J. A. Harker , Jordan Mirocha , Jack O. Burns , Jonathan R. Pritchard

Probing statistical distribution of the neutral hydrogen (\HI) using the redshifted 21-cm hyperfine-transition spectral line holds the key to understand the formation and evolution of the matter density in the universe. The two-point…

宇宙学与河外天体物理 · 物理学 2020-08-24 Urvashi Arora , Prasun Dutta

We propose a deep learning analyzing technique with convolutional neural network (CNN) to predict the evolutionary track of the Epoch of Reionization (EoR) from the 21-cm differential brightness temperature tomography images. We use…

宇宙学与河外天体物理 · 物理学 2020-07-15 Yungi Kwon , Sungwook E. Hong , Inkyu Park

Measurements of the post-reionization 21-cm bispectrum $B_{{\rm HI}}(\mathbf{k_1},\mathbf{k_2},\mathbf{k_3})$ using various upcoming intensity mapping experiments hold the potential for determining the cosmological parameters at a high…

宇宙学与河外天体物理 · 物理学 2019-10-16 Debanjan Sarkar , Suman Majumdar , Somnath Bharadwaj

The sky-averaged (global) highly redshifted 21-cm spectrum from neutral hydrogen is expected to appear in the VHF range of $\sim20-200$ MHz and its spectral shape and strength are determined by the heating properties of the first stars and…

天体物理仪器与方法 · 物理学 2018-10-24 Keith Tauscher , David Rapetti , Jack O. Burns , Eric R. Switzer

The cosmic radio-frequency spectrum is expected to show a strong absorption signal corresponding to the 21-centimetre-wavelength transition of atomic hydrogen around redshift 20, which arises from Lyman-alpha radiation from some of the…

宇宙学与河外天体物理 · 物理学 2018-03-20 Rennan Barkana

Distribution of cold gas in the post-reionization era provides an important link between distribution of galaxies and the process of star formation. Redshifted 21 cm radiation from the Hyperfine transition of neutral Hydrogen allows us to…

宇宙学与河外天体物理 · 物理学 2017-03-22 Bharat Kumar Gehlot , Jasjeet Singh Bagla

In the coming decade, low-frequency radio arrays will begin to probe the epoch of reionization via the redshifted 21-cm hydrogen line. Successful interpretation of these observations will require effective statistical techniques for…

宇宙学与河外天体物理 · 物理学 2015-05-19 Vera Gluscevic , Rennan Barkana

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…

天体物理学 · 物理学 2010-11-11 R. Benton Metcalf

Interferometry of the cosmic 21-cm signal is set to revolutionise our understanding of the Epoch of Reionisation (EoR) and the Cosmic Dawn (CD). The culmination of ongoing efforts will be the upcoming Square Kilometre Array (SKA), which…

宇宙学与河外天体物理 · 物理学 2020-01-08 Bradley Greig , Andrei Mesinger , Léon V. E. Koopmans

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…

天体物理学 · 物理学 2008-11-26 M. Valdes , A. Ferrara , M. Mapelli , E. Ripamonti

Neutral hydrogen (HI) serves as a crucial probe for the Cosmic Dawn and the Epoch of Reionization (EoR). Actual observations of the 21-cm signal often encounter challenges such as thermal noise and various systematic effects. To overcome…

We explore the prospects of upcoming 21-cm surveys of cosmic dawn ($12\lesssim \!z\lesssim\!30$) to provide cosmological information on top of upcoming cosmic microwave background (CMB) and large-scale structure surveys, such as CMB-S4,…

宇宙学与河外天体物理 · 物理学 2024-04-10 Nanoom Lee , Selim C. Hotinli

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…

The early star-forming Universe is still poorly constrained, with the properties of high-redshift stars, the first heating sources, and reionization highly uncertain. This leaves observers planning 21-cm experiments with little theoretical…

宇宙学与河外天体物理 · 物理学 2017-08-22 Aviad Cohen , Anastasia Fialkov , Rennan Barkana , Matan Lotem

Detecting the cosmic 21-cm signal during the Epoch of Reionisation and Cosmic Dawn will reveal insights into the properties of the first galaxies and advance cosmological parameter estimation. Until recently, the primary focus for…

宇宙学与河外天体物理 · 物理学 2022-04-20 Bradley Greig , Yuan-Sen Ting , Alexander A. Kaurov

The measurement of the large scale distribution of neutral hydrogen in the late Universe, obtained with radio telescopes through the hydrogen 21cm line emission, has the potential to become a key cosmological probe in the upcoming years. We…

宇宙学与河外天体物理 · 物理学 2023-03-15 Maria Berti , Marta Spinelli , Matteo Viel

The 21-cm signals from Cosmic Dawn and the Epoch of Reionization contain valuable information on cosmological structure formation dominated by dark matter. Measurements of the 21-cm power spectrum can thus probe certain dark matter…

宇宙学与河外天体物理 · 物理学 2025-08-15 Shihang Liu , Yilin Liu , Bowen Peng , Mengzhou Xie , Zelong Liu , Bohua Li , Yi Mao