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We have measured the properties of the diffractive scintillation toward the Vela pulsar under the extremely strong scattering conditions encountered at 660 MHz. We obtain a decorrelation bandwidth of $\nu_d = 244 \pm 4$ Hz and diffractive…

Astrophysics · Physics 2007-05-23 J. -P. Macquart , S. Johnston , M. Walker , D. Stinebring

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

Spatial distributions of electrons ionized and scattered from ultra-low pressure gases are proposed and experimentally demonstrated as a method to directly measure the intensity of an ultra-high intensity laser pulse. Analytic models…

Focusing control of ultrashort pulsed beams is an important research topic, due to its impact to subsequent interaction with matter. In this work, we study the propagation near the focus of ultrashort laser pulses of ~25 fs duration under…

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

Context: In addition to coherent pulsation, many accreting neutron stars exhibit flaring activity and strong aperiodic variability on time scales comparable to or shorter than their pulsation period. Such a behavior shows that the accretion…

High Energy Astrophysical Phenomena · Physics 2015-05-28 D. Klochkov , R. Staubert , A. Santangelo , R. E. Rothschild , C. Ferrigno

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

The distribution of the intensities of individual pulses of PSR B0950+08 as a function of the longitudes at which they appear is analyzed. The flux density of the pulsar at 111 MHz varies strongly from day to day (by up to a factor of 13)…

Astrophysics · Physics 2009-11-11 T. V. Smirnova

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

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…

We describe measurements of the size of the Vela pulsar via scintillation, using both fits to the distribution of intensity and measurements of the modulation index. We briefly discuss systematic effects other than source size that can…

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…

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

Refractive interstellar scintillation (RISS) is thought to be the cause behind a variety of phenomena seen at radio wavelengths in pulsars and compact radio sources. Though there is substantial observational data to support several…

Astrophysics · Physics 2009-10-31 N. D. Ramesh Bhat , A. Pramesh Rao , Yashwant Gupta

The flux density spectra of radio pulsars are known to be steep and, to first order, described by a power-law relationship of the form S_{\nu} \propto \nu^{\alpha}, where S_{\nu} is the flux density at some frequency \nu and \alpha is the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Samuel D. Bates , Duncan R. Lorimer , Joris P. W. Verbiest

We present average flux density measurements of 151 radio pulsars at 1.4 GHz with the Parkes 'Murriyang' radio telescope. We recommend our results be included in the next version of the ATNF pulsar catalogue. The large sample of pulsars…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Ziyang Wang , Jingbo Wang , Na Wang , Shi Dai , Jintao Xie

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…

Quasi-continuous observations of PSR B03239+54 over 20 days using the Nanshan 25-m telescope at 1540 MHz have been used to study the effects of refractive scintillation on the pulsar flux density and diffractive scintillation properties.…

Astrophysics · Physics 2009-11-13 N. Wang , Z. Yan , R. N. Manchester , H. X. Wang

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

In this paper we demonstrate that a large, unexplored reservoir of information about pulsar emission exists, that is directly linked to the radiating particles and their radiation process: We present a study of flux density measurements of…

Astrophysics · Physics 2009-11-10 M. Kramer , A. Karastergiou , Y. Gupta , S. Johnston , N. D. R. Bhat , A. G. Lyne