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We demonstrate that the sensitivity of high-precision pulsar timing experiments will be ultimately limited by the broadband intensity modulation that is intrinsic to the pulsar's stochastic radio signal. That is, as the peak flux of the…

Astrophysics of Galaxies · Physics 2011-09-23 Stefan Oslowski , Willem van Straten , George Hobbs , Matthew Bailes , Paul Demorest

This paper has been withdrawn from astro-ph and from the submission process to ApJ Letters since the variations "observed" are not real. As pointed out to me first by Willem van Straten and shortly thereafter by Matthew Bailes and Dick…

Interstellar scattering is known to broaden distant objects spatially and temporally. The latter aspect is difficult to analyse, unless the signals carry their own time stamps. Pulsars are so kind to do us this favour. Typically the…

Astrophysics of Galaxies · Physics 2019-04-26 Olaf Wucknitz

The Indian Pulsar Timing Array (InPTA) collaboration has recently made its first official data release (DR1) for a sample of 14 pulsars using 3.5 years of uGMRT observations. We present the results of single-pulsar noise analysis for each…

The Galactic interstellar turbulence affects the density distribution and star formation. We introduce a new method of measuring interstellar turbulent density spectra by using the dispersion measures (DMs) of a large sample of pulsars.…

Astrophysics of Galaxies · Physics 2021-01-06 Siyao Xu , Bing Zhang

We report on a recent global VLBI experiment in which we study the scatter broadening of pulsars in the spatial and time domain simultaneously. Depending on the distribution of scattering screen(s), geometry predicts that the less spatially…

Instrumentation and Methods for Astrophysics · Physics 2013-08-20 Olaf Wucknitz

Radio pulsars allow the study of the ionised interstellar medium and its dispersive effects, a major noise source in gravitational wave searches using pulsars. In this paper, we compare the functionality and reliability of three commonly…

In order to reach the sensitivity required to detect gravitational waves, pulsar timing array experiments need to mitigate as much noise as possible in timing data. A dominant amount of noise is likely due to variations in the dispersion…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 K. J. Lee , C. G. Bassa , G. H. Janssen , R. Karuppusamy , M. Kramer , K. Liu , D. Perrodin , R. Smits , B. W. Stappers , R. van Haasteren , L. Lentati

Pulsar Timing Arrays use a set of millisecond pulsars in an attempt to directly detect nanohertz gravitational waves. For this purpose, high precision timing of the pulsars is essential and ultimately a precision of the order of ~100 ns is…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Lina Levin

We report here on variable propagation effects in over twenty years of multi-frequency timing analysis of pulsar PSR B1937+21 that determine small-scale properties of the intervening plasma as it drifts through the sight line. The phase…

Astrophysics · Physics 2009-11-11 R. Ramachandran , P. Demorest , D. C. Backer , I. Cognard , A. Lommen

We present a mathematical analysis of propagation-induced distortions in the spectro-temporal properties of Fast Radio Bursts (FRBs). Within the Triggered Relativistic Dynamical Model, we derive a centroid-based formulation of the sub-burst…

High Energy Astrophysical Phenomena · Physics 2025-10-21 Aishwarya Kumar , Fereshteh Rajabi , Martin Houde

Common signal-processing approximations produce artefacts when timing pulsars in relativistic binary systems, especially edge-on systems with tight orbits, such as the Double Pulsar. In this paper, we use extensive simulations to explore…

High Energy Astrophysical Phenomena · Physics 2025-02-19 Huanchen Hu , Nataliya K. Porayko , Willem van Straten , Michael Kramer , David J. Champion , Michael J. Keith

The velocity and density distribution of $e^\pm$ in the pulsar wind are crucial distinction among magnetosphere models, and contains key parameters determining the high energy emission of pulsar binaries. In this work, a direct method is…

High Energy Astrophysical Phenomena · Physics 2017-10-11 Shu-Xu Yi , K. S. Cheng

It was recently suggested by Boldyrev & Gwinn that the characteristics of radio scintillations from distant pulsars are best understood if the interstellar electron-density fluctuations that cause the time broadening of the radio pulses…

Astrophysics · Physics 2010-11-11 Stanislav Boldyrev , Arieh Konigl

We measure the effects of interstellar scattering on average pulse profiles from 13 radio pulsars with simple pulse shapes. We use data from the LOFAR High Band Antennas, at frequencies between 110 and 190~MHz. We apply a forward fitting…

Efforts are underway to use high-precision timing of pulsars in order to detect low-frequency gravitational waves. A limit to this technique is the timing noise generated by dispersion in the plasma along the line of sight to the pulsar,…

High Energy Astrophysical Phenomena · Physics 2022-02-04 P. Kumar , S. M. White , K. Stovall , J. Dowell , G. B. Taylor

The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. 2013 was the first to show a short-term (~100-200 days) reduction in the electron content along the line of sight…

The following results of dissertation are submitted for defense: 1. Precise measurements of coordinates and proper motion of the pulsar PSR 0329+54 using the VLBI method. 2. Establishing of the reason for the discrepancy between the…

Instrumentation and Methods for Astrophysics · Physics 2024-01-25 Alexander Evgenievich Rodin

We present multi-wavelength scatter broadening observations of 47 pulsars, made with the Giant Metre-wave Radio Telescope (GMRT), Ooty Radio Telescope (ORT) and Long Wavelength Array (LWA). The GMRT observations have been made in the phased…

High Energy Astrophysical Phenomena · Physics 2017-09-13 M. A. Krishnakumar , Bhal Chandra Joshi , P. K. Manoharan