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Detecting the cosmological sky-averaged (global) 21 cm signal as a function of observed frequency will provide a powerful tool to study the ionization and thermal history of the intergalactic medium (IGM) in the early Universe ($\sim$ 400…

Instrumentation and Methods for Astrophysics · Physics 2019-09-30 Bang D. Nhan , David D. Bordenave , Richard F. Bradley , Jack O. Burns , Keith Tauscher , David Rapetti , Patricia J. Klima

Numerous studies have established the theoretical potential of the 21cm bispectrum to boost our understanding of the Epoch of Reionization (EoR), and therefore early generation of stars and galaxies. In this paper we look at the impact of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-09 Catherine A Watkinson , Cathryn M Trott , Ian Hothi

In this chapter, the use of machine learning (ML) in redshifted 21 cm cosmology is discussed, especially for the cosmic dawn, the Epoch of Reionization, and the scientific program of SKA-Low. The 21 cm signal is useful because it can…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-18 Hayato Shimabukuro

Background subtraction is a fundamental task in computer vision with numerous real-world applications, ranging from object tracking to video surveillance. Dynamic backgrounds poses a significant challenge here. Supervised deep…

Computer Vision and Pattern Recognition · Computer Science 2023-03-07 Fateme Bahri , Nilanjan Ray

The low surface brightness (LSB) regime ($\mu_{g} \gtrsim 26$ mag arcsec$^{-2}$) comprises a vast, mostly unexplored discovery space, from dwarf galaxies to the diffuse interstellar medium. Accessing this regime requires precisely removing…

Astrophysics of Galaxies · Physics 2024-01-24 A. E. Watkins , S. Kaviraj , C. C. Collins , J. H. Knapen , L. S. Kelvin , P. -A. Duc , J. Román , J. C. Mihos

The 21-cm signal from the Epoch of Reionization (EoR) is a powerful probe of the evolution of the Universe. However, accurate measurements of the EoR signal from radio interferometric observations are sensitive to efficient foreground…

Instrumentation and Methods for Astrophysics · Physics 2025-09-23 Madhurima Choudhury , Jonathan C. Pober

Recently, Differentiable Ray Tracing has been successfully applied in the field of wireless communications for learning radio materials or optimizing the transmitter orientation. However, in the frame of gradient based optimization,…

Signal Processing · Electrical Eng. & Systems 2024-04-30 Jerome Eertmans , Laurent Jacques , Claude Oestges

We investigate the 21 cm signals from the UV ionizing sources in the reionization epoch. The formation and evolution of 21 cm emission and absorption regions depend essentially on the kinetics of photons in the physical and frequency…

Astrophysics · Physics 2011-02-11 Jiren Liu , Jing-Mei Qiu , Long-Long Feng , Chi-Wang Shu , Li-Zhi Fang

The observed 21-cm signal from the epoch of reionization will be distorted along the line-of-sight by the peculiar velocities of matter particles. These redshift-space distortions will affect the contrast in the signal and will also make it…

The redshifted 21\,cm line is an emerging tool in observational cosmology that can serve as a direct probe of the intergalactic medium throughout the cosmic timeline. However, the observation of the cosmological 21\,cm signal from early…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-12 Samit Kumar Pal , Abhirup Datta , Aishrila Mazumder , Anshuman Tripathi

We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Steven G. Murray , Cathryn M. Trott , Christopher H. Jordan

Detection of the \hi~ 21-cm power spectrum is one of the key science drivers of several ongoing and upcoming low-frequency radio interferometers. However, the major challenge in such observations come from bright foregrounds, whose accurate…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-29 Madhurima Choudhury , Abhirup Datta , Suman Majumdar

Continuous symmetries are fundamental to many scientific and learning problems, yet they are often unknown a priori. Existing symmetry discovery approaches typically search directly in the space of transformation generators or rely on…

Machine Learning · Computer Science 2026-03-10 Pavan Karjol , Kumar Shubham , Prathosh AP

This paper presents a method for background removal in experimental data processing using the Dual-Tree Complex Wavelet Transform (DTCWT). The technique is based on discrete wavelet theory (DWT) and addresses limitations of commonly used…

We discuss the prospects for ``tomography'' of the intergalactic medium (IGM) at high redshifts using the 21 cm transition of neutral hydrogen. Existing observational constraints on the epoch of reionization imply a complex ionization…

Astrophysics · Physics 2009-11-10 Steven Furlanetto , Frank Briggs

Observation of redshifted 21-cm signals from neutral hydrogen holds the key to understanding the structure formation and its evolution during the reionization and post-reionization era. Apart from the presence of orders of magnitude larger…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Jais Kumar , Prasun Dutta , Samir Choudhuri , Nirupam Roy

A number of experiments are currently working towards a measurement of the 21 cm signal from the Epoch of Reionization. Whether or not these experiments deliver a detection of cosmological emission, their limited sensitivity will prevent…

We study the problem of passive imaging through convolutive channels. A scene is illuminated with an unknown, unstructured source, and the measured response is the convolution of this source with multiple channel responses, each of which is…

Information Theory · Computer Science 2017-08-25 Kiryung Lee , Felix Krahmer , Justin Romberg

Light rays incident on a transparent object of uniform refractive index undergo deflections, which uniquely characterize the surface geometry of the object. Associated with each point on the surface is a deflection map (or spectrum) which…

Computer Vision and Pattern Recognition · Computer Science 2015-07-15 Prasad Sudhakar , Laurent Jacques , Xavier Dubois , Philippe Antoine , Luc Joannes

In many astrophysical systems, smoothly-varying large-scale variations coexist with small-scale fluctuations. For example, a large-scale velocity or density gradient can exist in molecular clouds that exhibit small-scale turbulence. In…

Instrumentation and Methods for Astrophysics · Physics 2017-10-20 Jungyeon Cho
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