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We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the…

Astrophysics · Physics 2009-10-30 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Context. The spatially coherent multipath propagation of pulsar radiation leads to a temporal and spectral interference patterns called scintillation. It is caused by density variations in the ionized interstellar medium, which often take…

High Energy Astrophysical Phenomena · Physics 2026-05-15 Tim Sprenger , Xun Shi , Olaf Wucknitz , Robert A. Main

Low-frequency observations of pulsars provide a powerful means for probing the microstructure in the turbulent interstellar medium (ISM). Here we report on high-resolution dynamic spectral analysis of our observations of the timing-array…

Solar and Stellar Astrophysics · Physics 2016-02-17 N. D. R. Bhat , S. M. Ord , S. E. Tremblay , S. J. McSweeney , S. J. Tingay

The ionized interstellar medium contains au-scale (and below) structures that scatter radio waves from pulsars, resulting in scintillation. Power spectral analysis of scintillation often shows parabolic arcs, with curvatures that encode the…

Results from new observations of pulsars using the Ooty Radio Telescope (ORT) are used for investigating the structure of the Local Interstellar Medium (LISM). The observations show anomalous scintillation effects towards several nearby…

Astrophysics · Physics 2007-05-23 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao , P. B. Preethi

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

Recent pulsar scintillation measurements from Ooty, in conjunction with those from Parkes and other large radio telescopes, are used for a systematic investigation of the Local Interstellar Medium (LISM) towards the general direction of the…

Astrophysics · Physics 2009-11-07 N. D. Ramesh Bhat , Yashwant Gupta

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 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

Extreme scattering events (ESEs) in the interstellar medium (ISM) were first observed in regular flux measurements of compact extragalactic sources. They are characterized by a flux variation over a period of weeks, suggesting the passage…

We observed the scintillation pattern of nine bright pulsars at 324 MHz and three at 1.68 GHz and analyzed the wavenumber spectrum which is related to electron density variations of the plasma turbulence of the interstellar medium. For all…

Astrophysics of Galaxies · Physics 2022-12-21 N. Bartel , M. S. Burgin , E. N. Fadeev , M. V. Popov , N. Ronaghikhameneh , T. V. Smirnova , V. A. Soglasnov

Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium. If a pulsar is in a binary system, then investigating the orbital parameters is possible through analysis of the…

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

We studied the turbulence spectrum of the local interstellar plasma in the direction of PSR J0437-4715, on the basis of our observations and those reported earlier by others. We combine these data to form a structure function for the…

Astrophysics · Physics 2009-11-11 T. V. Smirnova , C. R. Gwinn , V. I. Shishov

Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array…

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

Interstellar scintillation analysis of pulsars allows us to probe the small-scale distribution and inhomogeneities of the ionized interstellar medium. Our priority is to present the data set and the basic measurements of scintillation…

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

We use the upgraded Giant Metrewave Radio Telescope to measure scintillation arc properties in six bright canonical pulsars with simultaneous dual frequency coverage. These observations at frequencies from 300 to 750 MHz allowed for…

High Energy Astrophysical Phenomena · Physics 2024-08-27 Jacob E. Turner , Bhal Chandra Joshi , Maura A. McLaughlin , Daniel R. Stinebring

We model long-term variations in the scintillation of binary pulsar PSR J1603$-$7202, observed by the 64 m Parkes radio telescope (Murriyang) between 2004 and 2016. We find that the time variation in the scintillation arc curvature is…

High Energy Astrophysical Phenomena · Physics 2022-07-06 Kris Walker , Daniel J. Reardon , Eric Thrane , Rory Smith