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The work describes a system for converting VLBI observation data using the algorithms of coherent dedispersion and compensation of two-bit signal sampling. Coherent dedispersion is important for processing pulsar observations to obtain the…

Instrumentation and Methods for Astrophysics · Physics 2023-03-31 Girin I. A. , Likhachev S. F. , Andrianov A. S. , Burgin M. S. , Popov M. V. , Rudnitskiy A. G. , Soglasnov V. A. , Zuga V. A

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

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 consider the role of a propagation effect such as the stimulated Raman scattering on the polarization of radio pulses. When an intense electromagnetic wave with frequency close to the plasma frequency interacts with the plasma in the…

Astrophysics · Physics 2009-10-31 R. T. Gangadhara , H. Lesch , V. Krishan

In recent years, instrumentation enabling pulsar observations with unprecedentedly high fractional bandwidth has been under development which can be used to substantially improve the precision of pulsar timing experiments. The traditional…

Radio pulsars scintillate because their emission travels through the ionized interstellar medium via multiple paths, which interfere with each other. It has long been realized that the scattering screens responsible for the scintillation…

High Energy Astrophysical Phenomena · Physics 2018-05-25 Robert Main , I-Sheng Yang , Victor Chan , Dongzi Li , Fang Xi Lin , Nikhil Mahajan , Ue-Li Pen , Keith Vanderlinde , Marten H. van Kerkwijk

This paper describes a comprehensive measurement model for the error budget of pulse arrival times with emphasis on intrinsic pulse jitterand plasma propagation effects (particularly interstellar scattering), which are stochastic in time…

Instrumentation and Methods for Astrophysics · Physics 2010-10-20 J. M. Cordes , R. M. Shannon

Defect detection by ultrasonic method is limited by the pulse width. Resolution can be improved through a deconvolution process with a priori information of the pulse or by its estimation. In this paper a regularization of the Wiener filter…

Information Theory · Computer Science 2012-05-17 Roberto H. Herrera , Eduardo Moreno , Héctor Calas , Rubén Orozco

The investigation of the Earth ionosphere both in a quiet and a disturbed states is still desirable. Despite recent progress in its modeling and in estimating the electron concentration along the line of sight by GPS signals, the impact of…

Earth and Planetary Astrophysics · Physics 2018-03-14 O. M. Ulyanov , A. I. Shevtsova , D. V. Mukha , A. A. Seredkina

Pulsars have been primarily detected by their narrow pulses or periodicity in time domain data. Interferometric surveys for pulsars are challenging due to the trade-off between beam sensitivity and beam size and the corresponding tradeoff…

High Energy Astrophysical Phenomena · Physics 2024-07-26 Jitendra Salal , Shriharsh P. Tendulkar , Visweshwar Ram Marthi

Pulsars are stars that emit electromagnetic radiation in well-defined time intervals. The frequency of such pulses decays with time as is quantified by the {\it braking index} ($n$). In the canonical model $n = 3$ for all pulsars, but…

High Energy Astrophysical Phenomena · Physics 2018-11-28 H. O. Oliveira , N. S. Magalhaes , R. M. Marinho , G. A. Carvalho , C. Frajuca

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

We are performing a transient, microsecond timescale radio sky survey, called "Astropulse," using the Arecibo telescope. Astropulse searches for brief (0.4 {\mu}s to 204.8 {\mu}s), wideband (relative to its 2.5 MHz bandwidth) radio pulses…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 J. Von Korff , P. Demorest , E. Heien , E. Korpela , D. Werthimer , J. Cobb , M. Lebofsky , D. Anderson , B. Bankay , A. Siemion

The observed spectra of 9 pulsars for which multiwavelength data are available from radio to $X$- or $\gamma$-ray bands (Crab, Vela, Geminga, B0656+14, B1055-52, B1509-58, B1706-44, B1929+10, and B1951+32) are compared with the spectrum of…

Astrophysics of Galaxies · Physics 2009-08-11 H. Ardavan , A. Ardavan , J. Singleton , J. Fasel , W. Junor , J. Middleditch , M. R. Perez , A. Schmidt , P. Sengupta , P. Volegov

Temporal scatter-broadening can seriously affect our ability to find pulsars orbiting the central mass in our Galaxy. Many of these invaluable probes of geometry around the black hole are expected, but none have been found in close orbits…

Astrophysics of Galaxies · Physics 2015-01-20 Olaf Wucknitz

We present the results of the multi-frequency scatter time measurements for ten radio pulsars that were relatively less studied in this regard. The observations were performed using the Giant Meterwave Radio Telescope at the observing…

High Energy Astrophysical Phenomena · Physics 2015-10-21 Wojciech Lewandowski , Karolina Rozko , Jaroslaw Kijak , Bhaswati Bhattacharyya , Jayanta Roy

A multilayered particle is illuminated by plane acoustic or electromagnetic waves of one or several frequencies. We consider the inverse scattering problem for the identification of the layers and of the refraction coefficients of the…

Mathematical Physics · Physics 2016-09-07 Semion Gutman

We present the first large sample of scintillation arcs in millisecond pulsars, analysing 12 sources observed with the Large European Array for Pulsars (LEAP), and the Effelsberg 100\,m telescope. We estimate the delays from multipath…

We present our results of pulse broadening time estimates and the study of the frequency scaling of this quantity for 60 pulsars based on actual multi-frequency scattering estimates. This research was based on our own measurements,…

Solar and Stellar Astrophysics · Physics 2015-06-23 Wojciech Lewandowski , Magdalena Kowalinska , Jaroslaw Kijak

In this work we study variations in the parabolic scintillation arcs of the binary millisecond pulsar PSR J1643-1224 over five years using the Large European Array for Pulsars (LEAP). The 2D power spectrum of scintillation, called the…

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