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The sparse layouts of radio interferometers result in an incomplete sampling of the sky in Fourier space which leads to artifacts in the reconstructed images. Cleaning these systematic effects is essential for the scientific use of…

As galaxy surveys begin to measure the imprint of baryonic acoustic oscillations (BAO) on large-scale structure at the sub-percent level, reconstruction techniques that reduce the contamination from nonlinear clustering become increasingly…

宇宙学与河外天体物理 · 物理学 2015-12-24 Marcel Schmittfull , Yu Feng , Florian Beutler , Blake Sherwin , Man Yat Chu

Accurate atmospheric profiles from remote sensing instruments such as Doppler Lidar, Radar, and radiometers are frequently corrupted by low-SNR (Signal to Noise Ratio) gates, range folding, and spurious discontinuities. Traditional gap…

机器学习 · 计算机科学 2026-01-15 Anurup Naskar , Nathanael Zhixin Wong , Sara Shamekh

We study the clustering of HI intensity maps produced from simulations with a focus on baryonic acoustic oscillations (BAO) and the effects induced by telescope beam smoothing and foreground cleaning. We start by creating a HI catalogue at…

宇宙学与河外天体物理 · 物理学 2021-12-13 Santiago Avila , Bernhard Vos-Ginés , Steven Cunnington , Adam R. H. Stevens , Gustavo Yepes , Alexander Knebe , Chia-Hsun Chuang

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

The baryon acoustic oscillations (BAO) prior to recombination should be imprinted onto the 21cm emission background from the epoch of reionization through the underlying density perturbations. Using an analytical approach for both matter…

天体物理学 · 物理学 2009-11-13 Xiao-Chun Mao , Xiang-Ping Wu

We train a deep learning artificial neural network model, Spatial Attention U-Net to recover useful ionospheric signals from noisy ionogram data measured by Hualien's Vertical Incidence Pulsed Ionospheric Radar. Our results show that the…

The future of precision cosmology could benefit from cross-correlations between intensity maps of unresolved neutral hydrogen (HI) and more conventional optical galaxy surveys. A major challenge that needs to be overcome is removing the…

宇宙学与河外天体物理 · 物理学 2019-07-17 Steven Cunnington , Laura Wolz , Alkistis Pourtsidou , David Bacon

We propose a deep learning analyzing technique with convolutional neural network (CNN) to predict the evolutionary track of the Epoch of Reionization (EoR) from the 21-cm differential brightness temperature tomography images. We use…

宇宙学与河外天体物理 · 物理学 2020-07-15 Yungi Kwon , Sungwook E. Hong , Inkyu Park

The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of the antenna used to make the observation coupling to the spectral inhomogeneity of these foregrounds. We…

天体物理仪器与方法 · 物理学 2021-11-12 Dominic Anstey , Eloy de Lera Acedo , Will Handley

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…

天体物理仪器与方法 · 物理学 2022-07-28 Shulei Ni , Yichao Li , Li-Yang Gao , Xin Zhang

We develop a framework for self-consistently extracting cosmological information from the clustering of tracers in redshift space, $\textit{without}$ relying on model-dependent templates to describe the baryon acoustic oscillation (BAO)…

宇宙学与河外天体物理 · 物理学 2023-09-11 Aseem Paranjape , Ravi K. Sheth

The 21-cm intensity mapping (IM) of neutral hydrogen (HI) is a promising tool to probe the large-scale structures. Sky maps of 21-cm intensities can be highly contaminated by different foregrounds, such as Galactic synchrotron radiation,…

宇宙学与河外天体物理 · 物理学 2021-12-01 Elimboto Yohana , Yin-Zhe Ma , Di Li , Xuelei Chen , Wei-Ming Dai

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…

宇宙学与河外天体物理 · 物理学 2023-01-18 Dominic Anstey , Eloy de Lera Acedo , Will Handley

We apply the reconstruction technique to the clustering of galaxies from the SDSS DR7 LRG sample, sharpening the baryon acoustic oscillation (BAO) feature and achieving a 1.9% measurement of the distance to z=0.35. This is the first…

宇宙学与河外天体物理 · 物理学 2015-06-04 Nikhil Padmanabhan , Xiaoying Xu , Daniel J. Eisenstein , Richard Scalzo , Antonio J. Cuesta , Kushal T. Mehta , Eyal Kazin

The redshifted 21 cm absorption trough from cosmic atomic hydrogen is one of the most promising probes of the early Universe, but its detection is challenged by bright foregrounds and instrumental systematics. In this work we quantify the…

Many works have investigated radio map and path loss prediction in wireless networks using deep learning, in particular using convolutional neural networks. However, most assume perfect environment information, which is unrealistic in…

信号处理 · 电气工程与系统科学 2026-02-13 Fabian Jaensch , Çağkan Yapar , Giuseppe Caire , Begüm Demir

When applying the foreground removal methods to uncover the faint cosmological signal from the epoch of reionization (EoR), the foreground spectra are assumed to be smooth. However, this assumption can be seriously violated in practice…

天体物理仪器与方法 · 物理学 2019-03-15 Weitian Li , Haiguang Xu , Zhixian Ma , Ruimin Zhu , Dan Hu , Zhenghao Zhu , Junhua Gu , Chenxi Shan , Jie Zhu , Xiang-Ping Wu

Motivated by recent developments in perturbative calculations of the nonlinear evolution of large-scale structure, we present an iterative algorithm to reconstruct the initial conditions in a given volume starting from the dark matter…

宇宙学与河外天体物理 · 物理学 2020-12-01 Marcel Schmittfull , Tobias Baldauf , Matias Zaldarriaga

21 cm intensity mapping has emerged as a promising technique to map the large-scale structure of the Universe, at redshifts $z$ from 1 to 10. Unfortunately, many of the key cross-correlations with the cosmic microwave background and…

宇宙学与河外天体物理 · 物理学 2018-11-20 Hong-Ming Zhu , Ue-Li Pen , Yu Yu , Xuelei Chen