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We use cyclic spectroscopy to directly measure the scintillation parameter $C_1$ for the millisecond pulsar B1937+21. This marks the first time this constant has been measured for any pulsar without assuming a pulse broadening function…

High Energy Astrophysical Phenomena · Physics 2026-05-27 Jacob E. Turner

Giant pulses from Crab pulsar were observed together with Radioastron space radiotelescope, Global EVN radio telescopes and Kvazar-KVO VLBI stations to study the scattering effects in the ISM. Five observing sessions were conducted at 18 cm…

Solar and Stellar Astrophysics · Physics 2015-05-06 Alexey Rudnitskiy , Mikhail Popov , Vladimir Soglasnov

We report on Westerbork Synthesis Radio Telescope observations of the Crab pulsar at 350 MHz from 2012 November 24 until 2015 June 21. During this period we consistently observe variations in the pulse profile of the Crab. Both variations…

High Energy Astrophysical Phenomena · Physics 2018-12-19 L. N. Driessen , G. H. Janssen , C. G. Bassa , B. W. Stappers , D. R. Stinebring

We determine the characteristics of the 7mm to 20cm wavelength radio variability in Sgr A* on time scales from days to three decades. The amplitude of the intensity modulation is between 30 and 39% at all wavelengths. Analysis of uniformly…

Astrophysics · Physics 2009-11-13 Jean-Pierre Macquart , Geoff Bower

Long-term studies of binary millisecond pulsars (MSPs) provide precise tests of strong-field gravity and can be used to measure neutron-star masses. PSR~J1909$-$3744, a binary MSP has been the subject of several pulsar timing analyses. The…

High Energy Astrophysical Phenomena · Physics 2022-11-09 Jacob Askew , Daniel Reardon , Ryan Shannon

We present here a method to study the distribution of electron density fluctuations in pulsar directions as well as to estimate pulsar distances. The method, based on a simple two-component model of the scattering medium discussed by Gwinn…

Astrophysics · Physics 2009-10-30 A. A. Deshpande , R. Ramachandran

We show that surface waves along interstellar current sheets closely aligned with the line of sight lead to pulsar scintillation properties consistent with those observed. This mechanism naturally produces the length and density scales of…

Astrophysics of Galaxies · Physics 2015-06-15 Ue-Li Pen , Yuri Levin

We present a large survey of giant pulses from the Crab Pulsar as observed with the first station of the Long Wavelength Array. Automated methods for detecting giant pulses at low frequencies where scattering becomes prevalent are also…

Solar and Stellar Astrophysics · Physics 2016-10-05 T. Eftekhari , K. Stovall , J. Dowell , F. K. Schinzel , G. B. Taylor

Using archival data from the 42 foot telescope at the Jodrell Bank Observatory, we produce daily stacks of aligned giant pulses for the Crab pulsar, to study changes to the daily profiles between April 2012 to December 2016. From these, we…

High Energy Astrophysical Phenomena · Physics 2023-12-20 Thierry Serafin Nadeau , Marten H. van Kerkwijk , Cees G. Bassa , Ben W. Stappers , Mitchell B. Mickaliger , Andrew G. Lyne

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

We present the detection of 107 pulsars with interstellar scintillation arcs at 856--1712\,MHz, observed with the MeerKAT Thousand Pulsar Array Programme. Scintillation arcs appear to be ubiquitous in clean, high S/N observations, their…

High Energy Astrophysical Phenomena · Physics 2022-11-17 R. A. Main , A. Parthasarathy , S. Johnston , A. Karastergiou , A. Basu , A. D. Cameron , M. J. Keith , L. S. Oswald , B. Posselt , D. J. Reardon , X. Song , P. Weltevrede

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

Pulsar timing at low frequencies offers a powerful tool for studying the interstellar medium. Additionally, pulsar observations in the ecliptic enables us to study the effects of the solar wind which becomes much more prominent at low radio…

High Energy Astrophysical Phenomena · Physics 2025-06-25 S. C. Susarla , O. A. Johnson , D. J. McKenna , E. F. Keane , P. J. McCauley , J. P. W. Verbiest , C. Tiburzi , A. Golden

Intensity scintillations of radio pulsars are known to originate from interference between waves scattered by the electron density irregularities of interstellar plasma, often leading to parabolic arcs in the two-dimensional power spectrum…

Pulsar scintillation observations have revealed ubiquitous discrete scintillation screens in the interstellar medium. A major obstacle in identifying the nature of these screens is the uncertainty in their distances, which prevents precise…

Astrophysics of Galaxies · Physics 2026-01-26 Yuanshang Huang , Xun Shi , Jumei Yao , Weiwei Zhu , Yonghua Xu

At the highest levels of pulsar timing precision achieved to date, experiments are limited by noise intrinsic to the pulsar. This stochastic wideband impulse modulated self-noise (SWIMS) limits pulsar timing precision by randomly biasing…

Instrumentation and Methods for Astrophysics · Physics 2013-01-23 Stefan Osłowski , Willem van Straten , Paul Demorest , Matthew Bailes

Ionospheric scintillation is the rapid change in the phase and/or the amplitude of a radio signal as it passes through small scale plasma density irregularities in the ionosphere. These scintillations not only can reduce the accuracy of…

Atmospheric and Oceanic Physics · Physics 2012-08-10 S. Priyadarshi , A. K. Singh

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

A pulsar timing system has been operating in the 18-cm band at the Urumqi Astronomical Observatory 25-m telescope since mid-1999. Frequency resolution allowing dedispersion of the pulsar signals is provided by a 2X128X2.5 MHz…

Astrophysics · Physics 2009-11-07 N. Wang , R. N. Manchester , J. Zhang , X. J. Wu , A. Yusup , A. G. Lyne , K. S. Cheng , M. Z. Chen