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Astrophysical foreground substraction is crucial to retrieve the cosmic microwave background (CMB) polarization out of the observed data. Recent efforts have been carried out towards the development of a minimally informed component…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Clément Leloup , Magdy Morshed , Arianna Rizzieri

In the neutral hydrogen (HI) intensity mapping (IM) survey, the foreground contamination on the cosmological signals is extremely severe, and the systematic effects caused by radio telescopes themselves further aggravate the difficulties in…

Instrumentation and Methods for Astrophysics · Physics 2022-07-28 Shulei Ni , Yichao Li , Li-Yang Gao , Xin Zhang

Non-linear growth of structure causes the gravitational potentials to grow with time, and this leaves an imprint on the small-scale temperature fluctuations of the Cosmic Microwave Background (CMB), a signal known as the Rees-Sciama (RS)…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-23 Simone Ferraro , Emmanuel Schaan , Elena Pierpaoli

Systematic effects that limit the achievable sensitivity of current low-frequency radio telescopes to the 21 cm signal are among the foremost challenges in observational 21 cm cosmology. The standard approach to retrieving the 21 cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 S. Munshi , L. V. E. Koopmans , F. G. Mertens , A. R. Offringa , S. A. Brackenhoff , E. Ceccotti , J. K. Chege , L. Y. Gao , S. Ghosh , M. Mevius , S. Zaroubi

We report the test results of several independent foreground-cleaning pipelines used in the Ali CMB Polarization Telescope experiment (AliCPT-1), a high-altitude CMB imager in the Northern hemisphere with thousands of detectors dedicated to…

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

We present new observations with the Precision Array for Probing the Epoch of Reionization (PAPER) with the aim of measuring the properties of foreground emission for 21cm Epoch of Reionization experiments at 150 MHz. We focus on the…

Current and future Cosmic Microwave Background (CMB) experiments aim to achieve high-precision reconstruction of the CMB polarization signal, with the most ambitious objective being the detection of primordial $B$ modes sourced by cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 Alessandro Carones

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

The \hi 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection of this signal. This paper investigates…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 A. Datta , J. D. Bowman , C. L. Carilli

In the quest for the faint primordial B-mode polarization of the Cosmic Microwave Background, three are the key requirements for any present or future experiment: an utmost sensitivity, excellent control over instrumental systematic effects…

Detecting cosmological signals from the Epoch of Reionization (EoR) requires high-precision calibration to isolate the cosmological signals from foreground emission. In radio interferometery, perturbed primary beams of antenna elements can…

Cross-correlations between 21cm observations and galaxy surveys provide a powerful probe of reionization by reducing foreground sensitivity while linking ionization morphology to galaxies. We quantify the constraining power of 21cm-Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Yannic Pietschke , Anne Hutter , Caroline Heneka

Observation of the 21cm line signal from neutral hydrogen during the Epoch of Reionization is challenging due to extremely bright Galactic and extragalactic foregrounds and complicated instrumental calibration. A reasonable approach for…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-12 S. Yoshiura , K. Ichiki , B. Pindor , K. Takahashi , H. Tashiro , C. M. Trott

All 21-cm signal experiments rely on electronic receivers that affect the data via both multiplicative and additive biases through the receiver's gain and noise temperature. While experiments attempt to remove these biases, the residuals of…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Keith Tauscher , David Rapetti , Bang D. Nhan , Alec Handy , Neil Bassett , Joshua Hibbard , David Bordenave , Richard F. Bradley , Jack O. Burns

Line intensity mapping (LIM) is a promising probe to study star formation, the large-scale structure of the Universe, and the epoch of reionization (EoR). Since carbon monoxide (CO) is the second most abundant molecule in the Universe…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-01 Xingchen Zhou , Yan Gong , Furen Deng , Meng Zhang , Bin Yue , Xuelei Chen

The 21 cm line provides a powerful probe of astrophysics and cosmology at high redshifts, but unlocking the potential of this probe requires the robust mitigation of foreground contaminants that are typically several orders of magnitude…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-25 Adrian Liu , Aaron R. Parsons , Cathryn M. Trott

We present a comprehensive analysis of the 21 cm intensity mapping (IM) data from the Tianlai Cylinder Pathfinder Array (TCPA), focusing on multi-scale foreground mitigation and three-dimensional power spectrum estimation. Utilizing 20 days…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-01 Yikai Deng , Shifan Zuo , Jixia Li , Yougang Wang , Xuelei Chen

We present a new approach to foreground removal for Cosmic Microwave Background (CMB) maps. Rather than relying on prior knowledge about the foreground components, we first extract the necessary information about them directly from the…

Astrophysics · Physics 2008-11-26 F. K. Hansen , A. J. Banday , H. K. Eriksen , K. M. Gorski , P. B. Lilje

The 21 cm hyperfine transition of neutral hydrogen offers a promising probe of the large scale structure of the universe before and during the Epoch of Reionization, when the first ionizing sources formed. Bright radio emission from…

Instrumentation and Methods for Astrophysics · Physics 2020-04-22 Adam E. Lanman , Jonathan C. Pober , Nicholas S. Kern , Eloy de Lera Acedo , David R. DeBoer , Nicolas Fagnoni