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In order to characterize and model the beam-weighted foreground for global 21-cm signal experiments, we present a methodology for generating basis eigenvectors that combines analytical and observational models of both the galactic spectral…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-06 Joshua J. Hibbard , Keith Tauscher , David Rapetti , Jack O. Burns

Precise estimation of cosmological parameters from the cosmic microwave background (CMB) remains a central goal of modern cosmology and a key test of inflationary physics. However, this task is fundamentally limited by strong foreground…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-03 Larissa Santos , Camila P. Novaes , Elisa G. M. Ferreira , Carlo Baccigalupi

Using the latest physical modeling and constrained by the most recent data, we develop a phenomenological parameterized model of the contributions to intensity and polarization maps at millimeter wavelengths from external galaxies and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Marius Millea , Olivier Doré , Jonathan Dudley , Gilbert Holder , Lloyd Knox , Laurie Shaw , Yong-Seon Song , Oliver Zahn

Before it becomes a sensitive probe of the Epoch of Reionization, the Dark Ages, and fundamental physics, 21 cm tomography must successfully contend with the issue of foreground contamination. Broadband foreground sources are expected to be…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-16 Adrian Liu , Max Tegmark

Global 21cm cosmology aims to investigate the cosmic dawn and epoch of reionisation by measuring the sky averaged HI absorption signal, which requires, accurate modelling of, or correction for, the bright radio foregrounds and distortions…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Dominic Anstey , Eloy de Lera Acedo , Will Handley

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

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

The recent tentative detection by the EDGES Low-Band antenna of the hydrogen 21-cm line from cosmic dawn, if confirmed, is the first ever signature observed from the epoch of primordial star formation. However, the magnitude and the shape…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Anastasia Fialkov , Rennan Barkana

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

Due to the large dynamic ranges involved with separating the cosmological 21-cm signal from the Cosmic Dawn from galactic foregrounds, a well-calibrated instrument is essential to avoid biases from instrumental systematics. In this paper we…

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

In the next decades, it is necessary to forge new late-universe cosmological probes to precisely constrain the Hubble constant and the equation of state of dark energy simultaneously. In this work, we show that the four typical…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-26 Peng-Ju Wu , Yue Shao , Shang-Jie Jin , Xin Zhang

A key challenge for current and upcoming CMB lensing measurements is their sensitivity to biases from extragalactic foregrounds, such as Sunyaev-Zeldovich (SZ) signals or cosmic infrared background emission. Several methods have been…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-02 Omar Darwish , Blake D. Sherwin , Noah Sailer , Emmanuel Schaan , Simone Ferraro

A key goal of many Cosmic Microwave Background experiments is the detection of gravitational waves, through their B-mode polarization signal at large scales. To extract such a signal requires modelling contamination from the Galaxy. Using…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Charmaine Armitage-Caplan , Joanna Dunkley , Hans Kristian Eriksen , Clive Dickinson

Aiming to correctly restore the redshifted 21 cm signals emitted by the neutral hydrogen during the cosmic reionization processes, we re-examine the separation approaches based on the quadratic polynomial fitting technique in frequency…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jingying Wang , Haiguang Xu , Tao An , Junhua Gu , Xueying Guo , Weitian Li , Yu Wang , Chengze Liu , Olivier Martineau-Huynh , Xiang-Ping Wu

We present an analysis of errors on the tensor-to-scalar ratio due to residual diffuse foregrounds. We use simulated observations of a CMB polarization satellite, the Cosmic Origins Explorer, using the specifications of the version proposed…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Carlos Hervías-Caimapo , Anna Bonaldi , Michael L. Brown

Potential evidence for primordial non-Gaussianity (PNG) is expected to lie in the largest scales mapped by cosmological surveys. Forthcoming 21cm intensity mapping experiments will aim to probe these scales by surveying neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-20 Steven Cunnington , Stefano Camera , Alkistis Pourtsidou

We compare multiple foreground-cleaning pipelines for estimating the tensor-to-scalar ratio, $r$, using simulated maps of the planned CMB-S4 experiment within the context of the South Pole Deep Patch. To evaluate robustness, we analyze bias…

[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

We present a method for calculating large numbers of power spectra C_l and P(k) that accelerates CMBfast by a factor around 10^3 without appreciable loss of accuracy, then apply it to constrain 11 cosmological parameters from current Cosmic…

Astrophysics · Physics 2009-10-07 Max Tegmark , Matias Zaldarriaga , Andrew J. S. Hamilton