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We have made high-resolution, high-sensitivity dynamic spectra of a sample of strong pulsars at 430 MHz with the Arecibo radiotelescope. For 4 pulsars we find faint but sharply delineated features in the secondary spectra. These are…

In extreme scattering events, the brightness of a compact radio source drops significantly, as light is refracted out of the line of sight by foreground plasma lenses. Despite recent efforts, the nature of these lenses has remained a…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Hengrui Zhu , Daniel Baker , Ue-Li Pen , Dan R. Stinebring , Marten H. van Kerkwijk

We have invented a novel technique to measure the radio image of a pulsar scattered by the interstellar plasma with 0.1 mas resolution. We extend the "secondary spectrum" analysis of parabolic arcs by Stinebring et al. (2001) to very long…

Weak interstellar scintillations of pulsar B0809+74 were observed at two epochs using a 30m EISCAT antenna at 933 MHz. These have been used to constrain the spectrum, the distribution and the transverse velocity of the scattering plasma…

Astrophysics · Physics 2015-06-24 Barney Rickett , Bill Coles , Jussi Markkanen

We use VLBI imaging of the interstellar scattering speckle pattern associated with the pulsar PSR 0834+06 to measure the astrometric motion of its emission. The ~ 5AU interstellar baselines, provided by interference between speckles…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Ue-Li Pen , J. P. Macquart , Adam Deller , Walter Brisken

Pulsar scintillation can be used to measure small scale structure in the Galaxy, but little is known about the specific interstellar medium features that cause scintillation. We searched for interstellar medium counterparts to all…

High Energy Astrophysical Phenomena · Physics 2025-06-04 Ashley M. Stock , Marten H. van Kerkwijk

Our analysis of archival VLBI data of PSR 0834+06 revealed that its scintillation properties can be precisely modelled using the inclined sheet model (Pen & Levin 2014), resulting in two distinct lens planes. These data strongly favour the…

Solar and Stellar Astrophysics · Physics 2016-02-17 Siqi Liu , Ue-Li Pen , J-P Macquart , Walter Brisken , Adam Deller

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

Pulsar scintillation allows a glimpse into small-scale plasma structures in the interstellar medium, if we can infer their properties from the scintillation pattern. With Very Long Baseline Interferometry and working in delay-delay rate…

Instrumentation and Methods for Astrophysics · Physics 2019-08-07 Dana Simard , Ue-Li Pen , Visweshwar Ram Marthi , Walter Brisken

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

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

Gravitational scattering events, in which the path of an interstellar object is deflected by a pulsar or the solar system, give rise to reflex motion which can potentially be detected using pulsar timing. We determine the form of the timing…

High Energy Astrophysical Phenomena · Physics 2020-02-12 Ross J. Jennings , James M. Cordes , Shami Chatterjee

We report on findings from scintillation analyses using high-cadence observations of eight canonical pulsars with observing baselines ranging from one to three years. We obtain scintillation bandwidth and timescale measurements for all…

Pulsar dynamic spectra exhibit high visibility fringes arising from interference between scattered radio waves. These fringes may be random or highly ordered patterns, depending on the nature of the scattering or refraction. Here we…

Astrophysics · Physics 2009-11-10 Mark Walker , Dan Stinebring

The aim of our work was to study the spatial structure of inhomogeneities of interstellar plasma in the directions of five pulsars: B0823+26, B0834+06, B1237+25, B1929+10, and B2016+28. Observations of these pulsars were made with…

We have searched for discrete refractive scattering events (including effects due to possible non-multiple diffractive scattering) at meter wavelengths in the direction of two close by pulsars B0950+08 and B1929+10, where we looked for…

Astrophysics · Physics 2007-05-23 R. Ramachandran , A. A. Deshpande , B. W. Stappers

In this paper, we report our investigation of pulsar scintillation phenomena by monitoring PSR B0355$+$54 at 2.25 GHz for three successive months using \emph{Kunming 40-m radio telescope}. We have measured the dynamic spectrum, the…

We have measured the scintillation properties of 151 young, energetic pulsars with the Parkes radio telescope and have identified two extreme scattering events (ESEs). Towards PSR J1057-5226 we discovered a three-year span of strengthened…

High Energy Astrophysical Phenomena · Physics 2017-12-27 M. Kerr , W. A. Coles , C. A. Ward , S. Johnston , A. V. Tuntsov , R. M. Shannon

Observations of pulsar scintillation are among the few astrophysical probes of very small-scale ($\lesssim$ au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and…

High Energy Astrophysical Phenomena · Physics 2023-11-28 S. K. Ocker , J. M. Cordes , S. Chatterjee , D. R. Stinebring , T. Dolch , V. Pelgrims , J. W. McKee , C. Giannakopoulos , D. J. Reardon

We report detections of scintillation arcs for pulsars in globular clusters M5, M13 and M15 for the first time using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From observations of these arcs at multiple epochs, we…

Astrophysics of Galaxies · Physics 2023-08-14 Dandan Zhang , Zhenzhao Tao , Mao Yuan , Jumei Yao , Pei Wang , Qijun Zhi , Weiwei Zhu , Xun Shi , Michael Kramer , Di Li , Lei Zhang , Guangxing Li
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