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The Square Kilometre Array (SKA) is intended as the next-generation radio telescope and will address fundamental questions in astrophysics, physics, and astrobiology. The international science community has developed a set of Key Science…

Instrumentation and Methods for Astrophysics · Physics 2009-10-06 Joseph Lazio

Context. Millimetre-wave astronomy is an important tool for both general astrophysics studies and cosmology. A large number of unidentified sources are being detected by the large field-of-view continuum instruments operating on large…

Instrumentation and Methods for Astrophysics · Physics 2023-03-29 Usasi Chowdhury , Florence Levy-Bertrand , Martino Calvo , Johannes Goupy , Alessandro Monfardini

The vast collecting area of the Square Kilometre Array (SKA), harnessed by sensitive receivers, flexible digital electronics and increased computational capacity, could permit the most sensitive and exhaustive search for…

Reconfigurable reflectarray antennas (RRAs) have rapidly developed with various prototypes proposed in recent literatures. However, designing wideband, multiband, or high-frequency RRAs faces great challenges, especially the lengthy…

Applied Physics · Physics 2023-10-09 Changhao Liu , You Wu , Songlin Zhou , Fan Yang , Yongli Ren , Shenheng Xu , Maokun Li

The concept of a Square Kilometre Array was developed to ensure that progress in Radio Astronomy in the early 21st Century continued at the same impressive pace as was achieved during the first 50 years. The SKA telescope is designed to…

Instrumentation and Methods for Astrophysics · Physics 2012-12-11 Lisa Harvey-Smith

Observationally, weak lensing has been served so far by optical surveys due to the much larger number densities of background galaxies achieved, which is typically by two to three orders of magnitude compared to radio. However, the high…

Instrumentation and Methods for Astrophysics · Physics 2016-03-18 Marzia Rivi , Lance Miller , Sphesihle Makhathini , Filipe Batoni Abdalla

Radio interferometers are phased arrays producing high-resolution images from the covariance matrix of measurements. Calibration of such instruments is necessary and is a critical task. This is how the estimation of instrumental errors is…

Instrumentation and Methods for Astrophysics · Physics 2023-09-26 Yassine Mhiri , Mohammed Nabil El Korso , Arnaud Breloy , Pascal Larzabal

The domain of radio astronomy is currently facing significant computational challenges, foremost amongst which are those posed by the development of the world's largest radio telescope, the Square Kilometre Array (SKA). Preliminary…

Instrumentation and Methods for Astrophysics · Physics 2016-11-17 R. J. Lyon , J. M. Brooke , J. D. Knowles , B. W. Stappers

This decade, the Square Kilometre Array (SKA) will perform its first observations. Preparations for building dishes, antennas, correlators and infrastructure are well underway. Concurrently, software for the processing of SKA observations…

Instrumentation and Methods for Astrophysics · Physics 2020-11-02 H. Spreeuw , S. Yatawatta , B. Van Werkhoven , F. Diblen

Radio Astronomy is undergoing a renaissance, as the next-generation of instruments provides a massive leap forward in collecting area and therefore raw sensitivity. However, to achieve this theoretical level of sensitivity in the science…

We present the largest survey to date characterising intended and unintended emission from Starlink satellites across the SKA-Low frequency range. This survey analyses ~76 million full sky images captured over ~29 days of observing with an…

Instrumentation and Methods for Astrophysics · Physics 2025-07-23 Dylan Grigg , Steven Tingay , Marcin Sokolowski

The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics (TA) of a circular region to a…

Classical Physics · Physics 2016-08-24 Alexey S. Titovich , Michael R. Haberman , Andrew N. Norris

Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric "radio window":…

This study introduces an novel approach to the design of low-profile superdirective antenna arrays, employing parasitic elements. The proposed design concept was verified through the analysis of a two-element antenna array consisting of…

Applied Physics · Physics 2024-02-20 James Moore , Aaron M. Graham , Manos M. Tentzeris , Vincent Fusco , Stylianos D. Asimonis

In the past two decades, a rebirth of interest in low-frequency radio astronomy for 21 cm tomography of the Epoch of Reionization, has given rise to a new class of radio interferometers with $N \gg 100$ antennas. The availability of…

Instrumentation and Methods for Astrophysics · Physics 2022-08-11 Deepthi Gorthi

The future new-generation radio telescope SKA (Square Kilometre Array) and its precursors will provide a rapidly growing number of polarized radio sources. Hundred and thousands polarized background sources can be measured towards nearby…

Astrophysics · Physics 2007-12-03 T. G. Arshakian , R. Stepanov , R. Beck , P. Frick , M. Krause

Microlensing is generally studied in the geometric optics limit. However, diffraction may be important when nearby substellar objects lens occult distant stars. In particular the effects of diffraction become more important as the…

Astrophysics of Galaxies · Physics 2010-10-05 Jeremy S. Heyl

Contemporary cosmic microwave background (CMB) experiments typically have observing bands covering the range 20 - 800 GHz. Certain science goals, including the detection of $\mu$-type distortions to the CMB spectrum and the characterization…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-07 David Zegeye , Thomas Crawford , Jens Chluba , Mathieu Remazeilles , Keith Grainge

The Square Kilometre Array's Low Frequency instrument (SKA-LOW) will be the most sensitive aperture array ever used for radio astronomy, and will operate in the under-sampled regime for most of the frequency band where grating-lobes pose…

Instrumentation and Methods for Astrophysics · Physics 2016-12-28 Benjamin Mort , Fred Dulwich , Nima Razavi-Ghods , Eloy de Lera Acedo , Keith Grainge