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Quantitative thermodynamical, dynamical and magnetic properties of the solar and stellar plasmas are obtained by interpreting their emergent non-polarized and polarized spectrum. This inference requires the selection of a set of spectral…

Solar and Stellar Astrophysics · Physics 2016-05-25 A. Asensio Ramos , J. de la Cruz Rodriguez , M. J. Martinez Gonzalez , A. Pastor Yabar

Optical interferometers may not require a phase-stable optical link between the stations if instead sources of quantum-mechanically entangled pairs could be provided to them, enabling long baselines. We developed a new variation of this…

Instrumentation and Methods for Astrophysics · Physics 2023-02-01 Zhi Chen , Andrei Nomerotski , Anže Slosar , Paul Stankus , Stephen Vintskevich

We provide tables of theoretical isochrones in several photometric systems. To this aim, the following steps are followed: (1) First, we re-write the formalism for converting synthetic stellar spectra into tables of bolometric corrections.…

We combine single- and two-photon interference procedures for characterizing any multi-port linear optical interferometer accurately and precisely. Accuracy is achieved by estimating and correcting systematic errors that arise due to…

Quantum Physics · Physics 2016-03-03 Ish Dhand , Abdullah Khalid , He Lu , Barry C. Sanders

In modern radio astronomy, one of the key technologies is to widen the frequency coverage of an instrument. The effects of higher-order modes on an instrument associated with wider bandwidths have been reported, which may degrade…

Instrumentation and Methods for Astrophysics · Physics 2024-03-19 Y. Yamasaki , H. Imada

Microwave, submillimetre-wave, and far-infrared phased arrays are of considerable importance for astronomy. We consider the behaviour imaging phased arrays and interferometric phased arrays from a functional perspective. It is shown that…

Astrophysics · Physics 2009-11-11 Stafford Withington , George Saklatvala , Michael P. Hobson

This paper provides a general introduction to the problem of image reconstruction from interferometric data. A simple model of the interferometric observables is given and the issues arising from sparse Fourier data are discussed. The…

Instrumentation and Methods for Astrophysics · Physics 2017-08-29 Éric Thiébaut , John Young

Many different methods exist for reducing data obtained when an astronomical source is studied with a two-channel polarimeter, such as a Wollaston prism system. This paper presents a rigorous method of reducing the data from raw aperture…

Astrophysics · Physics 2007-05-23 G. Leyshon

We present a pipeline that allows recovering reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the treatment of the instrumental effects already prior to the computation of the Stokes parameters…

Instrumentation and Methods for Astrophysics · Physics 2018-01-10 I. Myserlis , E. Angelakis , A. Kraus , C. A. Liontas , N. Marchili , M. F. Aller , H. D. Aller , V. Karamanavis , L. Fuhrmann , T. P. Krichbaum , J. A. Zensus

Light's polarisation contains information about its source and interactions, from distant stars to biological samples. Polarimeters can recover this information, but reliance on birefringent or rotating optical elements limits their…

Instrumentation and Detectors · Physics 2018-08-21 Ryan D. Hawley , John Cork , Neal Radwell , Sonja Franke-Arnold

We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 André Ferrari , Jérémy Deguignet , Chiara Ferrari , David Mary , Antony Schutz , Oleg Smirnov

When using valid foreground and signal models, the uncertainties on extracted signals in global 21-cm signal experiments depend principally on the overlap between signal and foreground models. In this paper, we investigate two strategies…

Instrumentation and Methods for Astrophysics · Physics 2020-07-22 Keith Tauscher , David Rapetti , Jack O. Burns

The number of publications of aperture-synthesis images based on optical long-baseline interferometry measurements has recently increased due to easier access to visible and infrared interferometers. The interferometry technique has now…

An eight stage balanced modulation scheme for dual beam polarimetry is presented in this paper. The four Stokes parameters are weighted equally in all the eight stages of modulation resulting in total polarimetric efficiency of unity. The…

Astrophysics · Physics 2007-10-10 K. Nagaraju , K. B. Ramesh , K. Sankarasubramanian , K. E. Rangarajan

Polarimetric studies of pulsar radio emission traditionally concentrate on how the Stokes vector (I, Q, U, V) varies with pulse longitude, with special emphasis on the position angle (PA) swing of the linearly polarized component. The…

Solar and Stellar Astrophysics · Physics 2011-03-08 C. T. Y. Chung , A. Melatos

We present a time-domain method to detect and correct spectral alterations of signals by employing statistical characterization of waveforms and a pattern-recognition procedure using simple Artificial Neural Networks. The proposed strategy…

Signal Processing · Electrical Eng. & Systems 2022-12-29 Guillermo H. Bustos , Héctor H. Segnorile

We present 36 observations of 17 visual binaries of moderate separation (range from 0.15'' to 0.79'') made with the 50 cm Cassegrain telescope of the Jagiellonian University in Cracow. The speckle interferometry technique was combined with…

Astrophysics · Physics 2009-11-11 Artur Rutkowski , Waclaw Waniak

Radio interferometry probes astrophysical signals through incomplete and noisy Fourier measurements. The theory of compressed sensing demonstrates that such measurements may actually suffice for accurate reconstruction of sparse or…

Astrophysics · Physics 2009-07-09 Y. Wiaux , L. Jacques , G. Puy , A. M. M. Scaife , P. Vandergheynst

Faraday tomography (or rotation measure synthesis) is a procedure to convert linear polarization spectra into the Faraday dispersion function, which provides us with unique information of magneto-ionic media along the line of sight.…

Instrumentation and Methods for Astrophysics · Physics 2018-12-03 Kazunori Akiyama , Takuya Akahori , Yoshimitsu Miyashita , Shinsuke Ideguchi , Ryosuke Yamaguchi , Shiro Ikeda , Keitaro Takahashi

At present, the principal limitation on the resolution and contrast of astronomical imaging instruments comes from aberrations in the optical path, which may be imposed by the Earth's turbulent atmosphere or by variations in the alignment…

Instrumentation and Methods for Astrophysics · Physics 2015-10-23 Benjamin Pope , Peter Tuthill , Sasha Hinkley , Michael J. Ireland , Alexandra Greenbaum , Alexey Latyshev , John D. Monnier , Frantz Martinache
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