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Time variable delays due to radio wave propagation in the ionized interstellar medium are a substantial source of error in pulsar timing array efforts. We describe the physical origin of these effects, discussing dispersive and scattering…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Dan Stinebring

The investigation of the statistical properties of maps of line centroids has been used for almost 50 years, but there is still no general agreement on their interpretation. We try to quantify which properties of underlying turbulent…

Astrophysics · Physics 2009-11-11 V. Ossenkopf , A. Esquivel , A. Lazarian , J. Stutzki

We examine statistical properties of a laser beam propagating in a turbulent medium. We prove that the intensity fluctuations at large propagation distances possess Gaussian probability density function and establish quantitative criteria…

Statistical Mechanics · Physics 2020-10-06 Igor Kolokolov , Vladimir Lebedev , Pavel M. Lushnikov

We have made observations of 98 low-Galactic-latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305-m Arecibo telescope at four radio frequencies…

Due to the inhomogeneity of electron number density, radio waves emitted by pulsars undergo scattering as they pass through the interstellar medium (ISM). However, a connection between large-scale pulsar scattering data and the structure of…

Astrophysics of Galaxies · Physics 2025-02-14 Qiuyi He , Xun Shi , Guangxing Li

The Very Local Interstellar Medium (VLISM) contains clouds which consist of partially-ionized plasma. These clouds can be effectively diagnosed via high resolution optical and ultraviolet spectroscopy of the absorption lines they form in…

Astrophysics of Galaxies · Physics 2015-05-19 Steven R. Spangler , Allison H. Savage , Seth Redfield

A strong case has been made that radio waves from sources within about half a degree of the Galactic Center undergo extreme diffractive scattering. However, problems arise when standard (``Kolmogorov'') models of electron density…

Astrophysics · Physics 2009-11-11 Peter Goldreich , S. Sridhar

We apply the scale-length method to several three dimensional samples of the Two degree Field Galaxy Redshift Survey. This method allows us to map in a quantitative and powerful way large scale structures in the distribution of galaxies…

Astrophysics · Physics 2009-08-03 Francesco Sylos Labini , Nikolay L. Vasilyev , Yurij V. Baryshev

Intraday variability (IDV) of compact extragalactic radio sources is a complex phenomenon and shows a wavelength dependent mixture of refractive interstellar scintillation (RISS) (dominant at long cm-wavelengths) and source-intrinsic…

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

Galactic dynamo models have generally relied on input parameters that are very challenging to constrain. We address this problem by developing a model that uses observable quantities as input: the galaxy rotation curve, the surface…

Astrophysics of Galaxies · Physics 2024-04-04 Luke Chamandy , Rion Glenn Nazareth , Gayathri Santhosh

Radio waves propagating through the interstellar medium are influenced by variations in plasma density. For spatially localised plasma structures along the line of sight, time-delay Doppler analyses of pulsars often reveal scintillation…

High Energy Astrophysical Phenomena · Physics 2026-05-15 Tobias Kramer

We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the…

High Energy Astrophysical Phenomena · Physics 2019-06-26 M. A. Krishnakumar , Yogesh Maan , Bhal Chandra Joshi , P. K. Manoharan

Blazars exhibit multiwavelength variability, a phenomenon whose underlying mechanisms remain elusive. This study investigates the origin of such variability through leptonic blazar emission simulations, focusing on stochastic fluctuations…

High Energy Astrophysical Phenomena · Physics 2024-09-10 Hannes Thiersen , Michael Zacharias , Markus Böttcher

The radio pulse from a pulsar can be temporally broadened by multipath scattering in the interstellar medium and by instrumental effects within the radio telescope. The observed pulse shape is a convolution of the intrinsic one with the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-09 M. M. McKinnon

Interstellar magnetic field is essential in various astrophysical phenomena and processes. Pulsar halos are a recently discovered class of TeV gamma-ray sources formed by escaping electrons/positrons from pulsars. The morphology of the halo…

High Energy Astrophysical Phenomena · Physics 2026-01-23 Chao-Ming Li , Ruo-Yu Liu , Huirong Yan

We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM). The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio…

Astrophysics of Galaxies · Physics 2015-06-15 Marijke Haverkorn , Steven R. Spangler

Pulsars are the only cosmic radio sources known to be sufficiently compact to show diffractive interstellar scintillations. Images of the variance of radio signals in both time and frequency can be used to detect pulsars in large-scale…

Instrumentation and Methods for Astrophysics · Physics 2016-08-17 S. Dai , S. Johnston , M. E. Bell , W. A. Coles , G. Hobbs , R. D. Ekers , E. Lenc

The power spectrum of HI intensity fluctuation of the interstellar medium carries information of the turbulence dynamics therein. We present a method to estimate the power spectrum of HI intensity fluctuation using radio interferometric…

Astrophysics of Galaxies · Physics 2009-05-22 Prasun Dutta , Ayesha Begum , Somnath Bharadwaj , Jayaram N. Chengalur

We give a new numerical model of pulsar pulse radiation through the interstellar medium (ISM) considering the propagation effects. It explains the deficit of a scattering measure at the decameter range of frequencies that leads to the…

Astrophysics of Galaxies · Physics 2015-06-11 O. M. Ulyanov , A. A. Seredkina , A. I. Shevtsova

We study the influence of a dissipation process on diffusion dynamics triggered by fluctuations with long-range correlations. We make the assumption that the perturbation process involved is of the same kind as those recently studied…

Statistical Mechanics · Physics 2007-05-23 M. Annunziato , P. Grigolini , J. Riccardi