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相关论文: Foreground removal in HI 21 cm intensity mapping u…

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We present a new halo model of neutral hydrogen (HI) calibrated to galaxy formation simulations at redshifts $z\sim0.1$ and $z\sim1.0$ that we employ to investigate the constraining power of interferometric HI intensity mapping on HI…

宇宙学与河外天体物理 · 物理学 2021-03-23 Zhaoting Chen , Laura Wolz , Marta Spinelli , Steven G. Murray

Upcoming 21-cm intensity surveys will use the hyperfine transition in emission to map out neutral hydrogen in large volumes of the universe. Unfortunately, large spatial scales are completely contaminated with spectrally smooth…

宇宙学与河外天体物理 · 物理学 2019-11-27 Chirag Modi , Martin White , Anze Slosar , Emanuele Castorina

With the rapid development of mobile devices, modern widely-used mobile phones typically allow users to capture 4K resolution (i.e., ultra-high-definition) images. However, for image demoireing, a challenging task in low-level vision,…

计算机视觉与模式识别 · 计算机科学 2022-07-21 Xin Yu , Peng Dai , Wenbo Li , Lan Ma , Jiajun Shen , Jia Li , Xiaojuan Qi

Recovering images corrupted by multiplicative noise is a well known challenging task. Motivated by the success of multiscale hierarchical decomposition methods (MHDM) in image processing, we adapt a variety of both classical and new…

数值分析 · 数学 2023-10-11 Joel Barnett , Wen Li , Elena Resmerita , Luminita Vese

Ground-based astronomical observations will continue to produce resolution-limited images due to atmospheric seeing. Deconvolution reverses such effects and thus can benefit extracted science in multifaceted ways. We apply the Scaled…

Foreground emission makes it difficult to detect the highly-redshifted cosmological 21 cm signal at any frequency. However, at low frequencies foregrounds are likely to become optically thick, which would make it completely impossible to…

宇宙学与河外天体物理 · 物理学 2022-05-18 Daniya Seitova , Jonathan C. Pober

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

We assess the performance of the multipole expansion formalism in the case of single-dish HI intensity mapping, including instrumental and foreground removal effects. This formalism is used to provide MCMC forecasts for a range of HI and…

宇宙学与河外天体物理 · 物理学 2021-01-13 Paula S. Soares , Steven Cunnington , Alkistis Pourtsidou , Chris Blake

We present an implementation of a blind source separation algorithm to remove foregrounds off millimeter surveys made by single-channel instruments. In order to make possible such a decomposition over single-wavelength data: we generate…

High-number-density tracers of large-scale structure, such as the HI-rich galaxies measured by 21 cm intensity mapping, have low sampling noise, making them particularly promising as cosmological probes. At large scales, this sampling noise…

宇宙学与河外天体物理 · 物理学 2024-10-28 Simon Foreman , Andrej Obuljen , Marko Simonović

The development of techniques for identifying hadronic signals from the overwhelming multi-jet backgrounds is an important part of the Large Hadron Collider (LHC) program. Of prime importance are resonances decaying into a pair of partons,…

高能物理 - 唯象学 · 物理学 2015-03-05 Eder Izaguirre , Brian Shuve , Itay Yavin

The existence of hybrid noise in hyperspectral images (HSIs) severely degrades the data quality, reduces the interpretation accuracy of HSIs, and restricts the subsequent HSIs applications. In this paper, the spatial-spectral gradient…

计算机视觉与模式识别 · 计算机科学 2019-10-23 Qiang Zhang , Qiangqiang Yuan , Jie Li , Xinxin Liu , Huanfeng Shen , Liangpei Zhang

Foreground removal is the most important step in detecting the large-scale redshifted HI 21-cm signal. Modelling foreground spectra is challenging and is further complicated by the chromatic response of the telescope. We present a…

天体物理仪器与方法 · 物理学 2017-07-19 Visweshwar Ram Marthi , Suman Chatterjee , Jayaram Chengalur , Somnath Bharadwaj

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

The all-sky 408 MHz map of Haslam et al. is one the most important total-power radio surveys. It has been widely used to study diffuse synchrotron radiation from our Galaxy and as a template to remove foregrounds in cosmic microwave…

天体物理仪器与方法 · 物理学 2015-06-11 M. Remazeilles , C. Dickinson , A. J. Banday , M. -A. Bigot-Sazy , T. Ghosh

Blind Source Separation (BSS) is a challenging matrix factorization problem that plays a central role in multichannel imaging science. In a large number of applications, such as astrophysics, current unmixing methods are limited since…

应用统计 · 统计学 2017-11-22 Ming Jiang , Jérôme Bobin , Jean-Luc Starck

Studies of the cosmic dark ages ($30 \lesssim z \lesssim 150$) using the highly redshifted 21 cm line of neutral hydrogen offer unparalleled amounts of cosmological information, and recent years have seen the refinement of concepts for such…

宇宙学与河外天体物理 · 物理学 2025-08-01 Jonathan C. Pober , Willow Smith

Current and upcoming 21-cm experiments will soon be able to map 21-cm spatial fluctuations in three dimensions for a wide range of redshifts. However, bright foreground contamination and the nature of radio interferometry create significant…

宇宙学与河外天体物理 · 物理学 2025-12-01 Shu-Fan Chen , Kai-Feng Chen , Cora Dvorkin

Hyperspectral image (HSI) denoising is a crucial step in enhancing the quality of HSIs. Noise modeling methods can fit noise distributions to generate synthetic HSIs to train denoising networks. However, the noise in captured HSIs is…

计算机视觉与模式识别 · 计算机科学 2025-11-24 Yingkai Zhang , Tao Zhang , Jing Nie , Ying Fu

In the absence of complex astrophysical processes that characterize the reionization era, the 21-cm emission from neutral hydrogen (HI) in the post-reionization epoch is believed to be an excellent tracer of the underlying dark matter…

宇宙学与河外天体物理 · 物理学 2015-05-30 Tapomoy Guha Sarkar , Sourav Mitra , Suman Majumdar , Tirthankar Roy Choudhury