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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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 2009-11-13 V. I. Kondratiev , M. V. Popov , V. A. Soglasnov , Y. Y. Kovalev , N. Bartel , W. Cannon , A. Yu. Novikov

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,…

太阳与恒星天体物理 · 物理学 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…

星系天体物理 · 物理学 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…

高能天体物理现象 · 物理学 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…

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…

星系天体物理 · 物理学 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…

高能天体物理现象 · 物理学 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…

星系天体物理 · 物理学 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…

天体物理学 · 物理学 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…

高能天体物理现象 · 物理学 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…

光学 · 物理学 2018-04-17 Chensheng Wu , Robert Lee , Christopher C. Davis