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We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Samir Choudhuri , Somnath Bharadwaj , Abhik Ghosh , SK. Saiyad Ali

Power spectrum estimators are an important tool in efforts to detect the 21 cm brightness temperature fluctuations from neutral hydrogen at early times. An initial detection will likely be statistical in nature, meaning that it will not be…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-24 Jacob Burba , Philip Bull , Michael J. Wilensky , Fraser Kennedy , Hugh Garsden , Katrine A. Glasscock

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…

This study aims to characterise the polarized foreground emission in the ELAIS-N1 field and to address its possible implications for the extraction of the cosmological 21-cm signal from the Low-Frequency Array - Epoch of Reionization…

Astrophysics of Galaxies · Physics 2014-09-05 V. Jelic , A. G. de Bruyn , M. Mevius , F. B. Abdalla , K. M. B. Asad , G. Bernardi , M. A. Brentjens , S. Bus , E. Chapman , B. Ciardi , S. Daiboo , E. R. Fernandez , A. Ghosh , G. Harker , H. Jensen , S. Kazemi , L. V. E. Koopmans , P. Labropoulos , O. Martinez-Rubi , G. Mellema , A. R. Offringa , V. N. Pandey , A. H. Patil , R. M. Thomas , H. K. Vedantham , V. Veligatla , S. Yatawatta , S. Zaroubi , A. Alexov , J. Anderson , I. M. Avruch , R. Beck , M. E. Bell , M. J. Bentum , P. Best , A. Bonafede , J. Bregman , F. Breitling , J. Broderick , W. N. Brouw , M. Bruggen , H. R. Butcher , J. E. Conway , F. de Gasperin , E. de Geus , A. Deller , R. -J. Dettmar , S. Duscha , J. Eisloffel , D. Engels , H. Falcke , R. A. Fallows , R. Fender , C. Ferrari , W. Frieswijk , M. A. Garrett , J. Griessmeier , A. W. Gunst , J. P. Hamaker , T. E. Hassall , M. Haverkorn , G. Heald , J. W. T. Hessels , M. Hoeft , J. Horandel , A. Horneffer , A. van der Horst , M. Iacobelli , E. Juette , A. Karastergiou , V. I. Kondratiev , M. Kramer , M. Kuniyoshi , G. Kuper , J. van Leeuwen , P. Maat , G. Mann , D. McKay-Bukowski , J. P. McKean , H. Munk , A. Nelles , M. J. Norden , H. Paas , M. Pandey-Pommier , G. Pietka , R. Pizzo , A. G. Polatidis , W. Reich , H. Rottgering , A. Rowlinson , A. M. M. Scaife , D. Schwarz , M. Serylak , O. Smirnov , M. Steinmetz , A. Stewart , M. Tagger , Y. Tang , C. Tasse , S. ter Veen , S. Thoudam , C. Toribio , R. Vermeulen , C. Vocks , R. J. van Weeren , R. A. M. J. Wijers , S. J. Wijnholds , O. Wucknitz , P. Zarka

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

Experiments aimed at detecting highly-redshifted 21 centimeter emission from the Epoch of Reionization (EoR) are plagued by the contamination of foreground emission. A potentially important source of contaminating foregrounds may be…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-13 David F. Moore , James E. Aguirre , Aaron R. Parsons , Daniel C. Jacobs , Jonathan C. Pober

Edge transport barriers (ETBs) in magnetically confined fusion plasmas, commonly known as pedestals, play a crucial role in achieving high confinement plasmas. However, their defining characteristic, a steep rise in plasma pressure over…

One of the critical challenges facing imaging studies of the 21-cm signal at the Epoch of Reionization (EoR) is the separation of astrophysical foreground contamination. These foregrounds are known to lie in a wedge-shaped region of…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-27 Samuel Gagnon-Hartman , Yue Cui , Jacob Kennedy , Adrian Liu , Siamak Ravanbakhsh

The 21 cm signal arising from fluctuations in the neutral hydrogen field, and its cross-correlation with other tracers of cosmic density, are promising probes of the high-redshift Universe. In this study, we assess the potential of the 21…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Barun Maity

We explore methods for robust estimation of the 21 cm signal from the Epoch of Reionisation (EoR). A Kernel Density Estimator (KDE) is introduced for measuring the spatial temperature fluctuation power spectrum from the EoR. The KDE…

We present new upper limits on the 21-cm signal power spectrum from the Epoch of Reionization (EoR), at redshifts $z \approx 10.1, 9.1, \text{ and } 8.3$, based on reprocessed observations from the Low-Frequency Array (LOFAR). The analysis…

An obstacle to the detection of redshifted 21cm emission from the epoch of reionization (EoR) is the presence of foregrounds which exceed the cosmological signal in intensity by orders of magnitude. We argue that in principle it would be…

Future gravitational wave (GW) standard siren catalogues will probe the late-time expansion history of the Universe across redshift ranges largely inaccessible to traditional electromagnetic observations. To determine how effectively this…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-27 Gourab Nandi , Anish Ghoshal , David F. Mota

The removal of the Galactic and extragalactic foregrounds remains a major challenge for those wishing to make a detection of the Epoch of Reionization 21-cm signal. Multiple methods of modelling these foregrounds with varying levels of…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-13 Emma Chapman , Saleem Zaroubi , Filipe Abdalla , Fred Dulwich , Vibor Jelić , Benjamin Mort

We develop and demonstrate an acceleration of the Liu & Tegmark quadratic estimator formalism for inverse variance foreground subtraction and power spectrum estimation in 21 cm tomography from O(N^3) to O(N log N), where N is the number of…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-22 Joshua S. Dillon , Adrian Liu , Max Tegmark

We present a comprehensive simulation-based study of the BayesEoR code for 21 cm power spectrum recovery when analytically marginalizing over foreground parameters. To account for covariance between the 21 cm signal and contaminating…

Instrumentation and Methods for Astrophysics · Physics 2023-02-09 Jacob Burba , Peter H. Sims , Jonathan C. Pober

Reconstruction of the sky brightness measured by radio interferometers is typically achieved through gridding techniques, or histograms in spatial Fourier space. For Epoch of Reionisation (EoR) 21 cm power spectrum measurements, extreme…

Instrumentation and Methods for Astrophysics · Physics 2022-04-22 Nichole Barry , Aman Chokshi

The overwhelming foreground contamination hinders the accurate detection of the 21-cm signal of neutral hydrogen during the Epoch of Reionization (EoR). Among various foreground components, the Galactic free-free emission is less studied,…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-11 Xiaoli Lian , Haiguang Xu , Zhenghao Zhu , Dan Hu

Retinal prostheses restore vision by electrically stimulating surviving neurons, but calibrating perceptual thresholds (i.e., the minimum stimulus intensity required for perception) remains a time-intensive challenge, especially for…

Quantitative Methods · Quantitative Biology 2025-04-30 Roksana Sadeghi , Michael Beyeler

The three-point correlation function (3PCF) of the 21cm brightness temperature from the Epoch of Reionization (EoR) probes complementary information to the commonly studied two-point correlation function (2PCF) about the morphology of…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-19 Kai Hoffmann , Yi Mao , Jiachuan Xu , Houjun Mo , Benjamin D. Wandelt