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We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550-750 MHz of the scintillation of PSR B1508+55, resulting in a $\sim$10,000-km baseline. This regime of measurement…

High Energy Astrophysical Phenomena · Physics 2021-08-18 V. R. Marthi , D. Simard , R. A. Main , U. -L. Pen , M. H. van Kerkwijk , K. Vanderlinde , Y. Gupta , C. Roberts , B. M. Quine

We report here a series of observations of the interstellar scintillation (ISS) of the double pulsar J0737$-$3039 over the course of 18 months. As in earlier work (Coles et al., 2005) the basic phenomenon is the variation in the ISS caused…

A model describing the coincidental timing of scintillating fibers is developed. Fiber geometry, the rate of scintillation decay together with the mean number, spatial dispersion and attenuation of emitted photons is considered. For a…

Instrumentation and Detectors · Physics 2011-11-04 Petar Žugec

We describe how the observed polarization properties of an astronomical object are related to its intrinsic polarization properties and the finite temporal and spectral resolutions of the observing device. Moreover, we discuss the effect…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Paz Beniamini , Pawan Kumar , Ramesh Narayan

We augment the two widest/deepest 1.4 GHz radio surveys: the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), with the mean epoch in which each source was observed. We use these catalogs to…

Astrophysics of Galaxies · Physics 2015-05-28 Eran O. Ofek , Dale A. Frail

Remote sensing hyperspectral and more generally spectral instruments are common tools to decipher surface features in Earth and Planetary science. While linear mixture is the most common approximation for compounds detection (mineral,…

Earth and Planetary Astrophysics · Physics 2023-05-03 Frédéric Schmidt

The simple 3-D radiative transfer model in the atmosphere of the Earth is built for numerical comparison of direct solar radiation and limb scattering background at the definite layer during the deep twilight period at the middle and upper…

Atmospheric and Oceanic Physics · Physics 2025-09-05 Oleg S. Ugolnikov

Despite some success in explaining the observed polarisation angle swing of radio pulsars within the geometric rotating vector model, many deviations from the expected S-like swing are observed. In this paper we provide a simple and…

Solar and Stellar Astrophysics · Physics 2009-11-13 A. Karastergiou

Microquasar stellar systems emit electromagnetic radiation and high-energy particles. Thanks to their location within our own galaxy, they can be observed in high detail. Still, many of their inner workings remain elusive; hence,…

High Energy Astrophysical Phenomena · Physics 2023-11-15 Theodoros Smponias

We report on the discovery of a source which exhibits over 300% amplitude changes in radio flux density on the period of hours. This source, J1819+3845, is the most extremely variable extragalactic source known in the radio sky. We believe…

Astrophysics · Physics 2009-10-31 J. Dennett-Thorpe , A. G. de Bruyn

The mechanisms for the formation of X-ray lines in the spectrum of SS 433 are investigated by taking into account the radiative transfer inside the jets. The results of Monte Carlo numerical simulations are presented. The effect of a…

High Energy Astrophysical Phenomena · Physics 2015-06-05 I. I. Khabibullin , S. Yu. Sazonov

The impact of mega-constellations of satellites in low-Earth orbit during nighttime optical observations is assessed. Orbital geometry is used to calculate the impact of stellar occultations by satellites on the photometry of individual…

Instrumentation and Methods for Astrophysics · Physics 2022-11-09 Paul J. Groot

In the solar convection zone acoustic waves are scattered by turbulent sound speed fluctuations. In this paper the scattering of waves by convective cells is treated using Rytov's technique. Particular care is taken to include diffraction…

Astrophysics · Physics 2009-10-31 M. Brüggen

We discuss the radiative transfer theory for translucent clouds illuminated by an extended background source. First we derive a rigorous solution based on the assumption that multiple scattering produce an isotropic flux. Then we derive a…

Solar and Stellar Astrophysics · Physics 2017-05-10 Davide Biganzoli , Marco Potenza , Massimo Robberto

Waves scattered by a weakly inhomogeneous random medium contain a predominant single scattering contribution as well as a multiple scattering contribution which is usually neglected, especially for imaging purposes. A method based on random…

Classical Physics · Physics 2015-03-13 Alexandre Aubry , Arnaud Derode

In radio bands, the study of compact radio sources can be affected by propagation effects through the Interstellar Medium. These are usually attributed to the presence of turbulent intervening plasma along the line of sight. Here, two of…

Astrophysics · Physics 2013-09-26 K. É. Gabányi , S. Britzen , T. P. Krichbaum , U. Bach , L. Fuhrmann , A. Kraus , A. Witzel , J. A. Zensus

The Doppler shift of a radio signal is caused by the relative motion between the transmitter and receiver. The change in frequency of the signal over time is called drift rate. In the studies of radio SETI (Search for Extraterrestrial…

Instrumentation and Methods for Astrophysics · Physics 2022-10-14 Jian-Kang Li , Haichen Zhao , Zhenzhao Tao , Tong-Jie Zhang , Sun Xiaohui

The modeling of stellar spectra is pervasive in astronomy. Conventionally, the shapes of absorption lines are modeled by convolving thermal profiles (computed given some model stellar atmosphere and line list) with broadening kernels…

Solar and Stellar Astrophysics · Physics 2025-12-11 Michael L. Palumbo

Scintillation arcs have become a powerful tool for exploring scattering in the ionized interstellar medium. There is accumulating evidence that the scattering from many pulsars is extremely anisotropic resulting in highly elongated, linear…

Astrophysics of Galaxies · Physics 2019-01-11 Dan R. Stinebring , Barney J. Rickett , Stella Koch Ocker

The use of the Van Cittert--Zernike theorem for the formulation of the visibility function in satellite-based Earth observation with passive radiometers does not take into account the relative motion of the observer (the satellite antenna)…

Data Analysis, Statistics and Probability · Physics 2015-12-09 Daniel Braun , Younes Monjid , Bernard Rougé , Yann Kerr