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We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser…

Antenna layout is an important design consideration for radio interferometers because it determines the quality of the snapshot point spread function (PSF, or array beam). This is particularly true for experiments targeting the 21 cm Epoch…

Atmospheric turbulence and precise measurement of the astrometric baseline vector between any two telescopes are two major challenges in implementing phase referenced interferometric astrometry and imaging. They limit the performance of a…

Instrumentation and Methods for Astrophysics · Physics 2018-03-14 N. Anugu , A. Amorim , P. Gordo , F. Eisenhauer , O. Pfuhl , M. Haug , E. Wiezorrek , J. Lima , G. Perrin , W. Brandner , C. Straubmeier , J. -B. Le Bouquin , P. J. V Garcia

This document presents a novel method for the intra-field calibration and imaging of the radio source SgrA*, observed with the Atacama Large Millimeter/submillimeter Array (ALMA). SgrA* is a complex source comprising two components: the…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Ezequiel Albentosa-Ruiz , Iván Martí-Vidal , Ciriaco Goddi , Alejandro Mus

A new method of angle estimation of multiple targets using a distributed interferometric antenna array and wideband space-time modulation is presented in this work. Interferometric array measurements of angle of arrival are generally…

Signal Processing · Electrical Eng. & Systems 2021-11-24 Stavros Vakalis , Jeffrey A. Nanzer

Modern Giant Segmented Mirror Telescopes (GSMTs) like the Extremely Large Telescope, which is currently under construction, depend heavily on Adaptive Optics (AO) systems to correct for atmospheric distortions. However, a residual blur…

Instrumentation and Methods for Astrophysics · Physics 2023-07-05 Roland Wagner , Jenny Niebsch , Ronny Ramlau

We derive a general formalism for interferometric visibilities, which considers first-order antenna-antenna coupling and assumes steady-state, incident radiation. We simulate such coupling features for non-polarized skies on a compact,…

Instrumentation and Methods for Astrophysics · Physics 2022-04-06 Alec T. Josaitis , Aaron Ewall-Wice , Nicolas Fagnoni , Eloy de Lera Acedo

Heterodyne receivers register the sky signal on either a circular polarization basis (where it is split into left-hand and right-hand circular polarization) or a linear polarization basis (where it is split into horizontal and vertical…

Instrumentation and Methods for Astrophysics · Physics 2016-03-09 Ivan Marti-Vidal , Alan Roy , John Conway , Anton J. Zensus

Phase referencing is a standard calibration procedure in radio interferometry. It allows to detect weak sources by using quasi-simultaneous observations of closeby sources acting as calibrators. Therefore, it is assumed that, for each…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal , J. C. Guirado , S. Jimenez-Monferrer , J. M. Marcaide

The detection of the primordial $B$-mode spectrum of the polarized cosmic microwave background (CMB) signal may provide a probe of inflation. However, observation of such a faint signal requires excellent control of systematic errors.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Ata Karakci , Le Zhang , P. M. Sutter , Emory F. Bunn , Andrei Korotkov , Peter Timbie , Gregory S. Tucker , Benjamin D. Wandelt

In this paper we present the electromagnetic modeling and beam pattern measurements of a 16-elements ultra wideband sparse random test array for the low frequency instrument of the Square Kilometer Array telescope. We discuss the importance…

Instrumentation and Methods for Astrophysics · Physics 2018-01-10 E. de Lera Acedo , P. Bolli , F. Paonessa , G. Virone , E. Colin-Beltran , N. Razavi-Ghods , I. Aicardi , A. Lingua , P. Maschio , J. Monari , G. Naldi , M. Piras , G. Pupillo

Radio-interferometric arrays require very precise calibration to detect the Epoch of Reionization 21-cm signal. A remarkably complete and accurate sky model is therefore needed in the patches of the sky used to perform the calibration.…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-13 Khandakar Md Asif Elahi , Samir Choudhuri , Nirupam Roy , Md Rashid , Philip Bull , Dharam Vir Lal

We study synergies between three promising methods to measure $2<z<5$ large-scale structure in the next decade. Optical spectroscopic surveys are the most mature, but become increasingly difficult at $z>2$ and suffer from interloper…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-24 Shi-Fan Chen , Emanuele Castorina , Martin White , Anže Slosar

Calibration of instrumental polarization is critical for measuring polarized radio emissions from astrophysical sources to extract the magnetic field information in astrophysical, heliospheric, and terrestrial plasmas. At meter wavelengths,…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Devojyoti Kansabanik , Angelos Vourlidas , Soham Dey , Surajit Mondal , Divya Oberoi

The Boolardy Engineering Test Array is a 6 x 12 m dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These…

Laser guide stars with adaptive optics allow astronomical image correction in the absence of a natural guide star. Single guide star systems with a star created in the earth's sodium layer can be used to correct the wavefront in the near…

Astrophysics · Physics 2009-11-11 S. Rabien , F. Eisenhauer , R. Genzel , R. I. Davies , T. Ott

Photoacoustic microscopy is becoming an important tool for the biomedical research. It has been widely used in biological researches, such as structural imaging of vasculature, brain structural and functional imaging, and tumor detection.…

Image and Video Processing · Electrical Eng. & Systems 2020-09-09 Xianlin Song , Jianshuang Wei , Lingfang Song

As Part I of a paper series showcasing a new imaging framework, we consider the recently proposed unconstrained Sparsity Averaging Reweighted Analysis (uSARA) optimisation algorithm for wide-field, high-resolution, high-dynamic range,…

Instrumentation and Methods for Astrophysics · Physics 2023-09-11 Amanda G. Wilber , Arwa Dabbech , Adrian Jackson , Yves Wiaux

Modern interferometers routinely provide radio-astronomical images down to subarcsecond resolution. However, interferometers filter out spatial scales larger than those sampled by the shortest baselines, which affects the measurement of…

Galactic all-sky maps at very disparate frequencies, like in the radio and $\gamma$-ray regime, show similar morphological structures. This mutual information reflects the imprint of the various physical components of the interstellar…