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21 cm tomography is expected to be difficult in part because of serious foreground contamination. Previous studies have found that line-of-sight approaches are capable of cleaning foregrounds to an acceptable level on large spatial scales,…

宇宙学与河外天体物理 · 物理学 2009-09-05 Adrian Liu , Max Tegmark , Judd Bowman , Jacqueline Hewitt , Matias Zaldarriaga

The 21 cm brightness temperature during the Epoch of Reionisation is widely modelled using semi-numeric simulations, used for their computational speed and flexibility in testing astrophysical and cosmological parameters. However, it is…

宇宙学与河外天体物理 · 物理学 2025-11-17 Jennifer Feron , Emma Chapman

The 21 cm line of neutral hydrogen is a promising probe of the Epoch of Reionization (EoR) but suffers from contamination by spectrally smooth foregrounds, which obscure the large-scale signal along the line of sight. We explore the…

宇宙学与河外天体物理 · 物理学 2026-02-26 Wenzer Qin , Kai-Feng Chen , Katelin Schutz , Adrian Liu

Predictions for the ability of 21-cm interferometric experiments to discriminate Epoch of Reionization (EoR) signal models are typically limited by the simplicity of data models, whereby foreground signals and characteristics of the…

宇宙学与河外天体物理 · 物理学 2020-04-29 Ainulnabilah Nasirudin , Steven Murray , Cathryn Trott , Bradley Greig , Ronniy Joseph , Chris Power

Measurement of the global 21-cm signal during Cosmic Dawn (CD) and the Epoch of Reionization (EoR) is made difficult by bright foreground emission which is 2-5 orders of magnitude larger than the expected signal. Fitting for a…

宇宙学与河外天体物理 · 物理学 2024-02-20 Michael Pagano , Peter Sims , Adrian Liu , Dominic Anstey , Will Handley , Eloy De Lera Acedo

Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract the cosmological signal (CS) from…

The observations of the redshifted 21-cm signal from neutral hydrogen are a promising probe for understanding the Cosmic Dawn and the Epoch of Reionisation (EoR). One of the primary obstacles to the statistical detection of the Cosmological…

宇宙学与河外天体物理 · 物理学 2026-05-22 Eeshan Beohar , Abhirup Datta , Anshuman Tripathi , Samit Kumar Pal , Rashmi Sagar

One of the aims of the Low Frequency Array (LOFAR) Epoch of Reionization (EoR) project is to measure the power spectrum of variations in the intensity of redshifted 21-cm radiation from the EoR. The sensitivity with which this power…

The first generation of redshifted 21 cm detection experiments, carried out with arrays like LOFAR, MWA and GMRT, will have a very low signal-to-noise ratio per resolution element (\sim 0.2). In addition, whereas the variance of the…

The key challenge in the observation of the redshifted 21-cm signal from cosmic reionization is its separation from the much brighter foreground emission. Such separation relies on the different spectral properties of the two components,…

Tomography of redshifted 21 cm transition from neutral Hydrogen using Fourier synthesis telescopes is a promising tool to study the Epoch of Reionization (EoR). Limiting the confusion from Galactic and Extragalactic foregrounds is critical…

天体物理仪器与方法 · 物理学 2015-05-28 Harish Vedantham , N. Udaya Shankar , Ravi Subrahmanyan

The redshifted 21~cm signal from neutral hydrogen (HI) is potentially a very powerful probe for cosmology, but a difficulty in its observation is that it is much weaker than foreground radiation from the Milky Way as well as extragalactic…

宇宙学与河外天体物理 · 物理学 2019-06-14 Shifan Zuo , Xuelei Chen , Reza Ansari , Youjun Lu

The BINGO radiotelescope will observe hydrogen distribution using Intensity Mapping (IM) to analyze the Dark Energy paradigm through Baryon Acoustic Oscillations. The target signal is contaminated by unwanted signals and instrumental noise,…

The redshifted 21 cm line of neutral hydrogen is a promising probe of the Epoch of Reionization (EoR). However, its detection requires a thorough understanding and control of the systematic errors. We study two systematic biases observed in…

For there to be a successful measurement of the 21 cm Epoch of Reionization (EoR) power spectrum, it is crucial that strong foreground contaminants be robustly suppressed. These foregrounds come from a variety of sources (such as Galactic…

宇宙学与河外天体物理 · 物理学 2014-07-25 Adrian Liu , Aaron R. Parsons , Cathryn M. Trott

We seek to remove foreground contaminants from 21cm intensity mapping observations. We demonstrate that a deep convolutional neural network (CNN) with a UNet architecture and three-dimensional convolutions, trained on simulated…

The exceptional sensitivity of the SKA will allow observations of the Cosmic Dawn and Epoch of Reionization (CD/EoR) in unprecedented detail, both spectrally and spatially. This wealth of information is buried under Galactic and…

Observations of the HI 21cm transition line promises to be an important probe into the cosmic dark ages and epoch of reionization. One of the challenges for the detection of this signal is the accuracy of the foreground source removal. This…

宇宙学与河外天体物理 · 物理学 2015-05-13 A. Datta , S. Bhatnagar , C. L. Carilli

Extracting the neutral hydrogen (HI) signal is a great challenge for cosmological 21cm experiments, both the astrophysical foregrounds and the receiver noise are typically several orders of magnitude greater than the 21cm signal. However,…

宇宙学与河外天体物理 · 物理学 2019-06-14 Qizhi Huang , Fengquan Wu , Reza Ansari , Xuelei Chen

Observations of the redshifted 21-cm signal emitted by neutral hydrogen represent a promising probe of large-scale structure in the universe. However, cosmological 21-cm signal is challenging to observe due to astrophysical foregrounds…

宇宙学与河外天体物理 · 物理学 2022-09-07 Haochen Wang , Juan Mena-Parra , Tianyue Chen , Kiyoshi Masui