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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

From 1979--1996 the Green Bank Interferometer was used by the Naval Research Laboratory to monitor the flux density from 146 compact radio sources at frequencies near 2 and 8 GHz. We filter the ``light curves'' to separate intrinsic…

Astrophysics · Physics 2009-11-11 B. Rickett , T. J. W. Lazio , F. D. Ghigo

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has observed dozens of millisecond pulsars for over a decade. We have accrued a large collection of dispersion measure (DM) measurements sensitive to the total…

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 caried out using the Ooty Radio Telescope (ORT) at 327 MHz, to investigate the distribution of ionized…

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

Density fluctuations in the ionised interstellar medium have a profound effect on radio pulsar observations, through angular scattering, intensity scintillations, and small changes in time delays from dispersion. Here we show that it is…

High Energy Astrophysical Phenomena · Physics 2023-04-12 Daniel J. Reardon , William A. Coles

We have observed the relativistic binary pulsar PSR J1141$-$6545 over a period of $\sim$6 years using the Parkes 64 m radio telescope, with a focus on modelling the diffractive intensity scintillations to improve the accuracy of the…

High Energy Astrophysical Phenomena · Physics 2019-03-20 D. J. Reardon , W. A. Coles , G. Hobbs , S. Ord , M. Kerr , M. Bailes , N. D. R. Bhat , V. Venkatraman Krishnan

Scintillation arcs have become a powerful tool for exploring scattering in the ionized interstellar medium. There is accumulating evidence that the scattering from many pulsars is extremely anisotropic resulting in highly elongated, linear…

Astrophysics of Galaxies · Physics 2019-01-11 Dan R. Stinebring , Barney J. Rickett , Stella Koch Ocker

We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550-750 MHz of the scintillation of PSR B1508+55, resulting in a $\sim$10,000-km baseline. This regime of measurement…

High Energy Astrophysical Phenomena · Physics 2021-08-18 V. R. Marthi , D. Simard , R. A. Main , U. -L. Pen , M. H. van Kerkwijk , K. Vanderlinde , Y. Gupta , C. Roberts , B. M. Quine

Broadband radio waves emitted from pulsars are distorted and delayed as they propagate toward the Earth due to interactions with the free electrons that compose the interstellar medium, with lower radio frequencies being more impacted than…

High Energy Astrophysical Phenomena · Physics 2023-06-12 Olivia Young , Michael Lam

We present the results of flux density monitoring of PSR B0329+54 at the frequency of 4.8 GHz using the 32-meter TCfA radiotelescope. The observations were conducted between 2002 and 2005. The main goal of the project was to find…

Astrophysics of Galaxies · Physics 2015-05-28 Wojciech Lewandowski , Jaroslaw Kijak , Yashwant Gupta , Krzysztof Krzeszowski

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…

The interstellar medium hosts a population of scattering screens, most of unknown origin. Scintillation studies of pulsars provides a sensitive tool for resolving these scattering screens and a means of measuring their properties. In this…

High Energy Astrophysical Phenomena · Physics 2022-03-14 James W. McKee , Hengrui Zhu , Daniel R. Stinebring , James M. Cordes

In certain pulsar timing experiments, where observations are scheduled approximately periodically (e.g. daily), timing models with significantly different frequencies (including but not limited to glitch models with different frequency…

High Energy Astrophysical Phenomena · Physics 2021-04-28 Liam Dunn , Marcus E. Lower , Andrew Melatos

We report multifrequency measurements of scatter broadening times for nine highly dispersed pulsars over a wide frequency range (0.6 -- 4.9 GHz). We find the scatter broadening times to be larger than expected and to scale with frequency…

Astrophysics · Physics 2009-11-07 O. Loehmer , M. Kramer , D. Mitra , D. R. Lorimer , A. G. Lyne

We apply a theory of wave propagation through a turbulent medium to the scattering of radio waves in pulsar magnetospheres. We find that under conditions of strong density modulation the effects of magnetospheric scintillations in…

Astrophysics · Physics 2009-10-31 Maxim Lyutikov , Anuj Parikh

The temporal smearing of impulsive radio events at cosmological redshifts probes the properties of the ionized Inter-Galactic Medium (IGM). We relate the degree of temporal smearing and the profile of a scattered source to the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jean-Pierre Macquart , Jun-Yi Koay

We use cyclic spectroscopy to perform high frequency-resolution analyses of multi-hour baseband Arecibo observations of the millisecond pulsar PSR B1937+21. This technique allows for the examination of scintillation features in far greater…

High sensitivity interstellar scintillation and polarization observations of PSR~B0656+14 made at three epochs over a year using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) show that the scattering is dominated by two…

High Energy Astrophysical Phenomena · Physics 2022-11-16 Jumei Yao , William A. Coles , Richard N. Manchester , Daniel R. Stinebring , Michael Kramer , Na Wang , Di Li , Weiwei Zhu , Yi Feng , Jianping Yuan , Pei Wang

In separate series of observations of the Crab pulsar, pulse broadening due to scattering was measured at 111 MHz, and variations of dispersion due to pulse delay were measured at higher radio frequencies. In a remarkable event lasting 200…

Astrophysics · Physics 2009-11-13 A. Kuzmin , B. Ya. Losovsky , C. A. Jordan , F. Graham Smith
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