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Scintillation spectra of some pulsars have suggested the existence of $\lesssim$ AU scale density structures in the ionized interstellar medium, whose astrophysical correspondence is still a mystery. The detailed study of Brisken et al.…

Astrophysics of Galaxies · Physics 2021-09-28 Xun Shi

A spatially-independent model that can be used to calculate the temporal evolution of the electron/ positron spectrum in a spherically expanding pulsar wind nebula is presented. The model is applied to the young nebula G21.5-0.9, as well as…

High Energy Astrophysical Phenomena · Physics 2013-08-08 M. J. Vorster , O. Tibolla , S. E. S. Ferreira , S. Kaufmann

We present a new technique for detecting scattered starlight from transiting, close-orbiting extrasolar giant planets (CEGPs) that has the virtues of simplicity, robustness, linearity, and model-independence. Given a series of stellar…

Properties of planetary atmospheres, ionospheres, and magnetospheres are difficult to measure from Earth. Radio occultations are a common method for measuring these properties, but they traditionally rely on radio transmissions from a…

Earth and Planetary Astrophysics · Physics 2017-02-24 Paul Withers , Marissa F. Vogt

We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-01 J. Y. Koay , J. -P. Macquart

The main idea and procedure are presented for a new synthetical method on constraining 3-D structure of emission regions of pulsars. With this method the emission regions can be synthetically constrained by fitting multi-wavelength…

Astrophysics · Physics 2007-05-23 H. G. Wang , H. Zhang , X. H. Cui , G. J. Qiao , K. J. Lee , Y. Liu , R. X. Xu

A tomographic method is described to quantify the three-dimensional power-spectrum of the ionospheric electron-density fluctuations based on radio-interferometric observations by a two-dimensional planar array. The method is valid to…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 L. V. E. Koopmans

Understanding the mechanism(s) of the solar wind acceleration is important in astrophysics and geophysics. A promising model of the solar wind acceleration is known as the wave/turbulence-driven (WTD) model, in which Alfv\'en waves feed…

Solar and Stellar Astrophysics · Physics 2022-04-13 Munehito Shoda , Kazumasa Iwai , Daikou Shiota

We present a simple but powerful technique for the analysis of polarized emission from radio galaxies and other objects. It is based on the fact that images of Stokes parameters often contain considerably more information than is available…

Astrophysics of Galaxies · Physics 2021-11-10 Lawrence Rudnick , Debora Katz , Lerato Sebokolodi

In this paper, we consider the 1D wave equation where the spatial domain is a bounded interval. Assuming the initial conditions to be known, we are here interested in identifying an unknown source term, while we take the Neumann derivative…

Optimization and Control · Mathematics 2011-06-30 Marianne Chapouly , Mazyar Mirrahimi

The parabolic structure of the secondary or conjugate spectra of pulsars is often the result of isolated one-dimensional (or at least highly anisotropic) lenses in the ISM. The curvature of these features contains information about the…

Instrumentation and Methods for Astrophysics · Physics 2023-07-11 Daniel Baker , Walter Brisken , Marten H. van Kerkwijk , Robert Main , Ue-Li Pen , Tim Sprenger , Olaf Wucknitz

The solar wind is a dynamic plasma outflow that shapes heliospheric conditions and drives space weather. Identifying its large-scale phenomena is crucial, yet the increasing volume of high-cadence Parker Solar Probe (PSP) observations poses…

Solar and Stellar Astrophysics · Physics 2025-11-03 Valmir P Moraes Filho , Daniela Martin , Jasmine R. Kobayashi , Connor O'Brien , Jinsu Hong , Evangelia Samara , Joseph Gallego

We present results from a leptonic emission code that models the spectral energy distribution of a pulsar wind nebula by solving a Fokker-Planck-type transport equation and calculating inverse Compton and synchrotron emissivities. We have…

High Energy Astrophysical Phenomena · Physics 2018-04-11 Carlo van Rensburg , Paulus Kruger , Christo Venter

The dynamical evolution and radiative properties of luminous radio galaxies and quasars of the FRII type, are well understood. As a result, through the use of detailed modeling of the observed radio emission of such sources, one can…

Astrophysics of Galaxies · Physics 2021-12-08 Anna Wojtowicz , Lukasz Stawarz , Jerzy Machalski , Luisa Ostorero

Direct observations of solar wind are mostly limited to the vicinity of the ecliptic plane. Retrieving the latitudinal structure of solar wind indirectly based on observations of the backscatter glow of interstellar neutral hydrogen is…

Solar and Stellar Astrophysics · Physics 2024-02-14 Izabela Kowalska-Leszczynska , Marzena A. Kubiak , Maciej Bzowski , Marek Strumik

Spatial distributions of electrons ionized and scattered from ultra-low pressure gases are proposed and experimentally demonstrated as a method to directly measure the intensity of an ultra-high intensity laser pulse. Analytic models…

This paper presents the model-based design and evaluation of an instrument that estimates incident neutron direction using the kinematics of neutron scattering by hydrogen-1 nuclei in an organic scintillator. The instrument design uses a…

Instrumentation and Detectors · Physics 2017-12-13 Kyle Weinfurther , John Mattingly , Erik Brubaker , John Steele

We examine the power spectra of IDV and show the information, which is to be gained by wavelet analysis of light curves of the quasar 0917+624. Results for total and polarized flux at 11cm are shown. Both interstellar scattering and…

Astrophysics · Physics 2007-05-23 T. Beckert , A. Kraus , T. P. Krichbaum , A. Witzel , J. A. Zensus

We develop a new method of extracting simultaneous measurements of weak lensing shear and a local rotation of the plane of polarization using observations of resolved radio sources. We show that the direction of polarization is…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-28 Lee Whittaker , Richard A. Battye , Michael L. Brown

Core and conal emission beams of radio pulsars have been identified observationally (Rankin 1983,1993; Lyne and Manchester 1988), In the inner gap model (Ruderman and Sutherland 1975, hereafter RS75), the gap continually breaks down…

Astrophysics · Physics 2009-09-25 G. J. Qiao , W. P. Lin