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We present new constraints on the 21cm Epoch of Reionization (EoR) power spectrum derived from 3 months of observing with a 32-antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of…

We study the viability of using power spectrum clustering wedges as summary statistics of 21cm surveys during the Epoch of Reionization (EoR). For observations in a wide redshift range $z\sim 7-9$ corresponding to a line-of-sight scale of…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-31 Zhaoting Chen , Alkistis Pourtsidou

Direction-dependent instrumental polarisation introduces wide-field polarimetric aberrations and limits the dynamic range of low-frequency interferometric images. We therefore provide a detailed two-dimensional analysis of the Giant…

Instrumentation and Methods for Astrophysics · Physics 2014-07-03 J. S. Farnes

The 21 cm bispectrum (BS) offers a powerful probe of the Epoch of Reionization (EoR), but its observational access is severely hindered by dominant astrophysical foregrounds. Considering Murchison Widefield Array (MWA) observations at…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Sukhdeep Singh Gill , Khandakar Md Asif Elahi , Somnath Bharadwaj , Shiv K. Sethi , Akash Kumar Patwa

We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization Array (HERA). Using similar analysis techniques as in…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-28 The HERA Collaboration , Zara Abdurashidova , Tyrone Adams , James E. Aguirre , Paul Alexander , Zaki S. Ali , Rushelle Baartman , Yanga Balfour , Rennan Barkana , Adam P. Beardsley , Gianni Bernardi , Tashalee S. Billings , Judd D. Bowman , Richard F. Bradley , Daniela Breitman , Philip Bull , Jacob Burba , Steve Carey , Chris L. Carilli , Carina Cheng , Samir Choudhuri , David R. DeBoer , Eloy de Lera Acedo , Matt Dexter , Joshua S. Dillon , John Ely , Aaron Ewall-Wice , Nicolas Fagnoni , Anastasia Fialkov , Randall Fritz , Steven R. Furlanetto , Kingsley Gale-Sides , Hugh Garsden , Brian Glendenning , Adélie Gorce , Deepthi Gorthi , Bradley Greig , Jasper Grobbelaar , Ziyaad Halday , Bryna J. Hazelton , Stefan Heimersheim , Jacqueline N. Hewitt , Jack Hickish , Daniel C. Jacobs , Austin Julius , Nicholas S. Kern , Joshua Kerrigan , Piyanat Kittiwisit , Saul A. Kohn , Matthew Kolopanis , Adam Lanman , Paul La Plante , David Lewis , Adrian Liu , Anita Loots , Yin-Zhe Ma , David H. E. MacMahon , Lourence Malan , Keith Malgas , Cresshim Malgas , Matthys Maree , Bradley Marero , Zachary E. Martinot , Lisa McBride , Andrei Mesinger , Jordan Mirocha , Mathakane Molewa , Miguel F. Morales , Tshegofalang Mosiane , Julian B. Muñoz , Steven G. Murray , Vighnesh Nagpal , Abraham R. Neben , Bojan Nikolic , Chuneeta D. Nunhokee , Hans Nuwegeld , Aaron R. Parsons , Robert Pascua , Nipanjana Patra , Samantha Pieterse , Yuxiang Qin , Nima Razavi-Ghods , James Robnett , Kathryn Rosie , Mario G. Santos , Peter Sims , Saurabh Singh , Craig Smith , Hilton Swarts , Jianrong Tan , Nithyanandan Thyagarajan , Michael J. Wilensky , Peter K. G. Williams , Pieter van Wyngaarden , Haoxuan Zheng

Radio polarimetry at decimetre wavelengths is the principal source of information on the Galactic magnetic field. The diffuse polarized emission is strongly influenced by Faraday rotation in the magneto-ionic medium and rotation measure is…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 M. Wolleben , T. L. Landecker , G. J. Hovey , R. Messing , O. S. Davison , N. L. House , K. H. M. S. Somaratne , I. Tashev

We have used semi-numerical simulations of reionization to study the behaviour of the power spectrum of the EoR 21-cm signal in redshift space. We have considered two models of reionization, one which has homogeneous recombination (HR) and…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-05 Suman Majumdar , Somnath Bharadwaj , T. Roy Choudhury

Interfacial polarization-charge accumulation at the heterointerface-is a well-established tool in semiconductors, but its influence in metals remains unexplored. Here, we demonstrate that interfacial polarization can robustly modulate…

The Epoch of Reionisation (EoR) is the period within which the neutral universe transitioned to an ionised one. This period remains unobserved using low-frequency radio interferometers which target the 21 cm signal of neutral hydrogen…

Instrumentation and Methods for Astrophysics · Physics 2021-07-01 J. Kariuki Chege , C. H. Jordan , C. Lynch , J. L. B. Line , C. M. Trott

The redshifted 21-cm signal is a unique probe of the early universe, particularly the Epoch of Reionization (EoR). While the 21-cm power spectrum has been the primary statistic for parameter inference, it fails to capture the non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-03 Anoop Krishna , Deepthi Moorkanat , Hiten , Rajesh Mondal

Visibility scintillation resulting from wave propagation through the turbulent ionosphere can be an important sources of noise at low radio frequencies ($\nu\lesssim 200$ MHz). Many low frequency experiments are underway to detect the power…

Instrumentation and Methods for Astrophysics · Physics 2016-03-16 H. K. Vedantham , L. V. E. Koopmans

The advent of a new generation of low frequency interferometers has opened a direct window into the Epoch of Reionisation (EoR). However, key to a detection of the faint 21-cm signal, and reaching the sensitivity limits of these arrays, is…

Instrumentation and Methods for Astrophysics · Physics 2018-12-05 Ronniy C. Joseph , Cathryn M. Trott , Randall B. Wayth

A critical challenge in measuring the power spectrum of 21cm emission from cosmic reionization is compensating for the frequency dependence of an interferometer's sampling pattern, which can cause smooth-spectrum foregrounds to appear…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 Aaron R. Parsons , Jonathan C. Pober , James E. Aguirre , Christopher L. Carilli , Daniel C. Jacobs , David F. Moore

The Epoch of Reionization Spectrometer (EoR-Spec) will be an instrument module for the Prime-Cam receiver on the CCAT-prime Collaboration's Fred Young Submillimeter Telescope (FYST), a 6-m primary mirror Crossed Dragone telescope. With its…

The redshifted $21$\,cm signal of neutral hydrogen can be used as a direct probe of the intergalactic medium during Cosmic Dawn\,(CD) and Epoch of Reionization\,(EoR). However, detecting this inherently weak signal has numerous challenges.…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-28 Samit Kumar Pal , Abhirup Datta , Aishrila Mazumder

We present a formalism to extract the EoR HI power spectrum for drift scans using radio interferometers. Our main aim is to determine the coherence time scale of time-ordered visibilities. We compute the two-point correlation function of…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-08 Akash Kumar Patwa , Shiv Sethi

The redshifted 21-cm signal from the epoch of reionization (EoR) directly probes the ionization and thermal states of the intergalactic medium during that period. In particular, the distribution of the ionized regions around the radiating…

Next generation radio telescope arrays are being designed and commissioned to accurately measure polarized intensity and rotation measures across the entire sky through deep, wide-field radio interferometric surveys. Radio interferometer…

Instrumentation and Methods for Astrophysics · Physics 2017-08-02 P. Jagannathan , S. Bhatnagar , U. Rau , A. R. Taylor

The EoR 21-cm signal is expected to become highly non-Gaussian as reionization progresses. This severely affects the error-covariance of the EoR 21-cm power spectrum which is important for predicting the prospects of a detection with…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-14 Rajesh Mondal , Somnath Bharadwaj , Suman Majumdar