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Related papers: Inference from the 21cm signal

200 papers

The formation of the first stars and the subsequent population of X-ray binaries represents a fundamental transition in the state of the Universe as it evolves from near homogeneity to being abundant in collapsed structures such as…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 T. Gessey-Jones , N. S. Sartorio , H. T. J. Bevins , A. Fialkov , W. J. Handley , E. de Lera Acedo , G. M. Mirouh , R. G. Izzard , R. Barkana

Modern machine learning will allow for simulation-based inference from reionization-era 21cm observations at the Square Kilometre Array. Our framework combines a convolutional summary network and a conditional invertible network through a…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-16 Benedikt Schosser , Caroline Heneka , Tilman Plehn

A crucial physical quantity in determining the 21-cm signal during cosmic dawn is the inhomogeneous background of Ly$\alpha$ photons originating from the first galaxies. As these photons travel through the intergalactic medium, their…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-22 Jordan Flitter , Julian B. Muñoz , Andrei Mesinger

The sky-averaged, or global, background of redshifted $21$ cm radiation is expected to be a rich source of information on cosmological reheating and reionizaton. However, measuring the signal is technically challenging: one must extract a…

Instrumentation and Methods for Astrophysics · Physics 2016-08-03 Tejaswi Venumadhav , Tzu-Ching Chang , Olivier Doré , Christopher M. Hirata

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

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…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Bradley Greig , Yuan-Sen Ting , Alexander A. Kaurov

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

In this short review I present the status of the global 21-cm signal detected by EDGES in March 2018. It is organized in three parts. First, I present the EDGES experiment and the fitting procedure used by the collaboration to extract the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-16 Paolo Panci

The high-redshift 21-cm signal of neutral hydrogen is expected to be observed within the next decade and will reveal epochs of cosmic evolution that have been previously inaccessible. Due to the lack of observations, many of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Aviad Cohen , Anastasia Fialkov , Rennan Barkana

The redshifted 21-cm signal from the Cosmic Dawn and Epoch of Reionization carries invaluable information about the cosmology and astrophysics of the early Universe. Analyzing data from a sky-averaged 21-cm signal experiment requires…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Anchal Saxena , P. Daniel Meerburg , Christoph Weniger , Eloy de Lera Acedo , Will Handley

Observations of the redshifted 21-cm signal (in absorption or emission) allow us to peek into the epoch of "dark ages" and the onset of reionization. These data can provide a novel way to learn about the nature of dark matter, in particular…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-11 Alexey Boyarsky , Dmytro Iakubovskyi , Oleg Ruchayskiy , Anton Rudakovskyi , Wessel Valkenburg

Fluctuations in the 21cm brightness from cosmic hydrogen at redshifts z > 6 were sourced by the primordial density perturbations from inflation as well as by the radiation from galaxies. We propose a method to separate these components…

Astrophysics · Physics 2009-11-10 Rennan Barkana , Abraham Loeb

The cosmic 21-cm signal is a promising probe of the early Universe, owing to its sensitivity to the thermal state of the neutral intergalactic medium (IGM) and properties of the first luminous sources. Here, we constrain the 21-cm signal…

We present detailed predictions for the redshifted 21cm signal from the epoch of reionization. These predictions are obtained from radiative transfer calculations on the results of large scale (100/h Mpc), high dynamic range, cosmological…

Astrophysics · Physics 2009-11-11 Garrelt Mellema , Ilian T. Iliev , Ue-Li Pen , Paul R. Shapiro

The extraction of the sky-averaged 21 cm signal from Cosmic Dawn and the Epoch of Reionization faces significant challenges. The bright and anisotropic Galactic foreground, which is 4 - 5 orders of magnitude brighter than the 21 cm signal,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-10 Haoran Li , Furen Deng , Meng Zhou , Yidong Xu , Xuelei Chen

We present an investigation of the horizon and its effect on global 21-cm observations and analysis. We find that the horizon cannot be ignored when modeling low frequency observations. Even if the sky and antenna beam are known exactly,…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-15 Neil Bassett , David Rapetti , Keith Tauscher , Bang D. Nhan , David D. Bordenave , Joshua J. Hibbard , Jack O. Burns

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…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-20 Rennan Barkana

One of the main challenges for future 21 cm observations is to remove foregrounds which are several orders of magnitude more intense than the HI signal. We propose a new technique for removing foregrounds of the redshifted 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jungyeon Cho , A. Lazarian , P. Timbie

Accurate beam modeling is important in many radio astronomy applications. In this paper, we focus on beam modeling for 21-cm intensity mapping experiments using radio interferometers, though the techniques also apply to single dish…

Instrumentation and Methods for Astrophysics · Physics 2025-09-16 Michael J. Wilensky , Philip Bull , Nicolas Fagnoni

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