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In this paper, we describe a novel experiment for the accurate estimation of pulsar dispersion measures using the Giant Metre-wave Radio Telescope. This experiment was carried out for a sample of twelve pulsars, over a period of more than…

Astrophysics · Physics 2009-11-10 A. L. Ahuja , Y. Gupta , D. Mitra , A. K. Kembhavi

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

Scintillation observations of the nearby single millisecond pulsar (MSP) PSR J0030+0451 were carried out with the Parkes 64m radiotelescope at three different epochs in 1999. From analysis of the dynamic spectrum we obtained the amplitude…

Astrophysics · Physics 2009-11-06 L. Nicastro , F. Nigro , N. D'Amico , V. Lumiella , S. Johnston

Diffractive and refractive magnetospheric scintillations may allow a direct testing of the plasma inside the light cylinder. Unusual electrodynamics of the strongly magnetized electron-positron plasma allow separation of the magnetospheric…

Astrophysics · Physics 2009-10-31 Maxim Lyutikov

The dust shell around the evolved star HD 179821 has been detected in scattered light in near-IR imaging polarimetry observations. Here, we subtract the contribution of the unpolarized stellar light to obtain an intrinsic linear…

Astrophysics · Physics 2009-11-07 T. M. Gledhill , M. Takami

(Abridged) In the first part of this thesis, a general methodology for applying image deconvolution to wide-field CCD imagery. Results show that wavelet-based deconvolution can increase limiting magnitude up to 0.6 mag and improve limiting…

Astrophysics · Physics 2007-05-23 O. Fors

VLBI observations of the Crab pulsar with the 64-m radio telescope at Kalyazin (Russia) and the 46-m radio telescope of the Algonquin Radio Observatory (Canada) at 2.2 GHz and single-dish observations of the millisecond pulsar B1937+21 with…

We present our results of pulse broadening time estimates and the study of the frequency scaling of this quantity for 60 pulsars based on actual multi-frequency scattering estimates. This research was based on our own measurements,…

Solar and Stellar Astrophysics · Physics 2015-06-23 Wojciech Lewandowski , Magdalena Kowalinska , Jaroslaw Kijak

We compare signal and noise for observations of the scintillating pulsar B0834+06, using very-long baseline interferometry and a single-dish spectrometer. Comparisons between instruments and with models suggest that amplitude variations of…

Astrophysics of Galaxies · Physics 2015-05-27 C. R. Gwinn , M. D. Johnson , T. V. Smirnova , D. R. Stinebring

RadioAstron space-ground VLBI observations of the pulsar B0950+08, conducted with the 10-m space radio telescope in conjunction with the Arecibo 300-m telescope and Westerbork Synthesis Radio Telescope at a frequency of 324 MHz, were…

We have measured variations in scattering time scales in the Crab Pulsar over a 30-year period, using observations made at 610 MHz with the 42-ft telescope at Jodrell Bank Observatory. Over more recent years, where regular Lovell Telescope…

High Energy Astrophysical Phenomena · Physics 2018-07-18 J. W. McKee , A. G. Lyne , B. W. Stappers , C. G. Bassa , C. A. Jordan

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

We have detected substructure within the smooth scattering disk of the celebrated Galactic Center radio source Sagittarius A* (SgrA*). We observed this structure at 1.3 cm wavelength with the Very Long Baseline Array together with the Green…

Astrophysics of Galaxies · Physics 2014-10-03 C. R. Gwinn , Y. Y. Kovalev , M. D. Johnson , V. A. Soglasnov

We conducted radio interferometric observations of six pulsars at 610 MHz using the Giant Metrewave Radio Telescope (GMRT). All these objects were claimed or suspected to be the gigahertz-peaked spectra (GPS) pulsars. For a half of the…

High Energy Astrophysical Phenomena · Physics 2015-06-24 M. Dembska , R. Basu , J. Kijak , W. Lewandowski

The wide survey of the Chinese Space Station Telescope (CSST) will observe a large field of 17,500 $\text{deg}^2$. The GU, GV, and GI grism observations of CSST will cover a wavelength range from 2550 to 10000\r{A} at a resolution of $R\sim…

Astrophysics of Galaxies · Physics 2025-01-23 Yuxuan Pang , Xue-Bing Wu , Yuming Fu , Rui Zhu , Bing Lyu , Huimei Wang , Xiaotong Feng

We sought to determine the scale of scintillation in the interstellar plasma of PSR J0437-4715. We used the Very Long Baseline Array to obtain scintillation amplitude and phase data, from dynamic spectra at 327 MHz. We observe two scales of…

Astrophysics · Physics 2015-06-24 C. R. Gwinn , C. Hirano , S. Boldyrev

The high sensitivity and wide frequency coverage of the Murchison Widefield Array allow for the measurement of the spectral scaling of the pulsar scattering timescale, $\alpha$, from a single observation. Here we present three case studies…

High Energy Astrophysical Phenomena · Physics 2019-04-17 F. Kirsten , N. D. R. Bhat , B. W. Meyers , J. -P. Macquart , S. E. Tremblay , S. M. Ord

The scattering of light observed through the turbid underwater channel is often regarded as the leading challenge when designing underwater electro-optical imaging systems. There have been many approaches to address the effects of…

Optics · Physics 2018-04-17 Chensheng Wu , Robert Lee , Christopher C. Davis