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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

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…

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

Observations of the 21cm Epoch of Reionization (EoR) signal are dominated by Galactic and extragalactic foregrounds. The need for foreground removal has led to the development of two main techniques, often referred to as "foreground…

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…

宇宙学与河外天体物理 · 物理学 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

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…

宇宙学与河外天体物理 · 物理学 2015-05-30 Xiao-Chun Mao

21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a…

宇宙学与河外天体物理 · 物理学 2011-06-02 Adrian Liu , Max Tegmark

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…

宇宙学与河外天体物理 · 物理学 2015-06-04 Jungyeon Cho , A. Lazarian , P. Timbie

A proposed method for dealing with foreground emission in upcoming 21-cm observations from the epoch of reionization is to limit observations to an uncontaminated window in Fourier space. Foreground emission can be avoided in this way,…

宇宙学与河外天体物理 · 物理学 2015-12-23 Hannes Jensen , Suman Majumdar , Garrelt Mellema , Adam Lidz , Ilian T. Iliev , Keri L. Dixon

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…

宇宙学与河外天体物理 · 物理学 2012-01-16 Adrian Liu , Max Tegmark

Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

宇宙学与河外天体物理 · 物理学 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

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…

宇宙学与河外天体物理 · 物理学 2024-03-13 Feng Shi , Haoxiang Chang , Le Zhang , Huanyuan Shan , Jiajun Zhang , Suiping Zhou , Ming Jiang , Zitong Wang

Twenty-one centimeter tomography is emerging as a powerful tool to explore the end of the cosmic dark ages and the reionization epoch, but it will only be as good as our ability to accurately model and remove astrophysical foreground…

天体物理学 · 物理学 2008-11-26 Xiaomin Wang , Max Tegmark , Mario Santos , Lloyd Knox

In order to study the "Cosmic Dawn" and the Epoch of Reionization with 21 cm tomography, we need to statistically separate the cosmological signal from foregrounds known to be orders of magnitude brighter. Over the last few years, we have…

We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra…

宇宙学与河外天体物理 · 物理学 2015-06-16 Junhua Gu , Haiguang Xu , Jingying Wang , Tao An , Wen Chen

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…

宇宙学与河外天体物理 · 物理学 2018-08-22 F. Mertens , A. Ghosh , L. V. E. Koopmans

The cosmological global (sky-averaged) 21-cm signal is a powerful tool to probe the evolution of the intergalactic medium (IGM) in high-redshift Universe ($z \leq 6$). One of the biggest observational challenges is to remove the foreground…

天体物理仪器与方法 · 物理学 2018-11-14 Bang D. Nhan , Richard F. Bradley , Jack O. Burns

The epoch of reionization power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints on the physics of reionization. The primary obstacle to the…

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