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After reionization, neutral hydrogen (HI) traces the large-scale structure (LSS) of the Universe, enabling HI intensity mapping (IM) to capture the LSS in 3D and constrain key cosmological parameters. We present a new framework utilizing…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-10 Eishica Chand , Arka Banerjee , Simon Foreman , Francisco Villaescusa-Navarro

Intensity mapping is a promising technique for surveying the large scale structure of our Universe from $z=0$ to $z \sim 150$, using the brightness temperature field of spectral lines to directly observe previously unexplored portions of…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 Adrian Liu , Yunfan Zhang , Aaron R. Parsons

The ability to subtract foreground contamination from low-frequency observations is crucial to reveal the underlying 21 cm signal. The traditional line-of-sight methods can deal with the removal of diffuse emission and unresolved point…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Xiao-Chun Mao

The technique of intensity mapping (IM) has emerged as a powerful tool to explore the universe at $z < 6$. IM measures the integrated emission from sources over a broad range of frequencies, unlocking significantly more information than…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-01 Hamsa Padmanabhan

Cosmological analyses of samples of photometrically-identified Type Ia supernovae (SNe Ia) depend on understanding the effects of 'contamination' from core-collapse and peculiar SN Ia events. We employ a rigorous analysis on…

Deep imaging of structures from the Cosmic Dawn (CD) and the Epoch of Reionization (EoR) in five targeted fields is one of the highest priority scientific objectives for the Square Kilometre Array (SKA). Selecting 'quiet' fields, which…

Instrumentation and Methods for Astrophysics · Physics 2025-07-14 Xueying Zhang , Qian Zheng , Linhui Wu , Quan Guo , Stefan W. Duchesne , Mengfan He , Huanyuan Shan , Xiang-ping Wu , Melanie Johnston-Hollitt , Feiyu Zhao , Qingyuan Ma

We present a framework for forecasting cosmological constraints from future neutral hydrogen intensity mapping experiments at low to intermediate redshifts. In the process, we establish a simple way of comparing such surveys with optical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-08 Philip Bull , Pedro G. Ferreira , Prina Patel , Mario G. Santos

The intensity mapping of the [CII] 157.7 $\rm \mu$m fine-structure emission line represents an ideal experiment to probe star formation activity in galaxies, especially in those that are too faint to be individually detected. Here, we…

Astrophysics of Galaxies · Physics 2015-05-27 Bin Yue , Andrea Ferrara , Andrea Pallottini , Simona Gallerani , Livia Vallini

In order to extract cosmological information from observations of the millimeter and submillimeter sky, foreground components must first be removed to produce an estimate of the cosmic microwave background (CMB). We developed a…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-10 Matthew A. Petroff , Graeme E. Addison , Charles L. Bennett , Janet L. Weiland

21 cm intensity mapping has arisen as a powerful probe of the high-redshift universe, but its potential is limited by extremely bright foregrounds and high source confusion. In this Letter, we propose a new analysis which can help solve…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-11 Patrick C. Breysse , Christopher J. Anderson , Philippe Berger

The deep learning technique has been employed in removing foreground contaminants from 21 cm intensity mapping, but its effectiveness is limited by the large dynamic range of the foreground amplitude. In this study, we develop a novel…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-13 Feng Shi , Haoxiang Chang , Le Zhang , Huanyuan Shan , Jiajun Zhang , Suiping Zhou , Ming Jiang , Zitong Wang

We present a realistic simulation of an SKA-Low cosmic dawn/epoch of reionisation (CD/EoR) observation, which can be used to further the development of foreground-mitigation approaches. The simulation corresponds to a deep (1000 h)…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-18 Anna Bonaldi , Philippa Hartley , Simon Purser , Omkar Bait , Eunseong Lee , Robert Braun , Florent Mertens , Andrea Bracco , Wendy Williams , Cath Trott

This paper introduces a technique called NKL, which cleans both polarized and unpolarized foregrounds from HI intensity maps by applying a Karhunen-Lo\`eve transform on the needlet coefficients. In NKL, one takes advantage of correlations…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-03 John Podczerwinski , Peter Timbie

Precise measurement of the foreground synchrotron emission, which contaminates the faint polarized cosmic microwave background radiation (CMB), is a major challenge for the next-generation of CMB experiments. To address this, dedicated…

Studies of cosmic microwave background (CMB) are often limited by foreground contamination. Foreground cleaning is performed either in harmonic or pixel space after data cuts have excluded sky areas of strong contamination. We present a…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-05 Hayley C. Nofi , Graeme E. Addison , Charles L. Bennett , Laura Herold , J. L. Weiland

We present early science results from Deep Investigation of Neutral Gas Origins (DINGO), an HI survey using the Australian Square Kilometre Array Pathfinder (ASKAP). Using ASKAP sub-arrays available during its commissioning phase, DINGO…

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

A new and promising technique for observing the Universe and study the dark sector is the intensity mapping of the redshifted 21cm line of neutral hydrogen (HI). The BINGO radio telescope will use the 21cm line to map the Universe in the…

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…

Instrumentation and Methods for Astrophysics · Physics 2023-03-29 Aishrila Mazumder , Abhirup Datta , Mayuri Sathyanarayana Rao , Arnab Chakraborty , Saurabh Singh , Anshuman Tripathi , Madhurima Choudhury

This white paper envisions a revolutionary post-DESI, post-LSST dark energy program based on intensity mapping of the redshifted 21cm emission line from neutral hydrogen at radio frequencies. The proposed intensity mapping survey has the…

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