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相关论文: Interstellar Plasma Turbulence Spectrum Toward the…

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The emission geometries, e.g. the emission region height, the beam shape, and radius-to-frequency mapping, are important predictions of pulsar radiation model. The multi-band radio observations carry such valuable information. In this…

We have collected pulsar flux density observations and compiled spectra of 281 objects. The database of Lorimer et al. (\cite{lorimer}) has been extended to frequencies higher than 1.4 GHz and lower than 300 MHz. Our results show that above…

天体物理学 · 物理学 2009-10-31 Olaf Maron , Jaroslaw Kijak , Michael Kramer , Richard Wielebinski

Comparing the asymmetry coefficients and scintillation indices for observed time variations of the intensity of the radiation of extragalactic sources and the predictions of theoretical models is a good test of the nature of the observed…

天体物理学 · 物理学 2009-11-11 V. I. Shishov , T. V. Smirnova , S. A. Tyul'bashev

The radio continuum spectra of pulsars (PSRs) exhibit a wide variety of shapes, that are interpreted as pure and broken power laws, power laws with turnovers or cut-offs, and logarithmic-parabolic profiles. A notable fraction of these have…

星系天体物理 · 物理学 2025-11-24 Mario G. Abadi , Gabriela Castelletti , Namir E. Kassim

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…

天体物理学 · 物理学 2009-11-11 B. Rickett , T. J. W. Lazio , F. D. Ghigo

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

Spatially-resolved gas pressure maps of the Coma galaxy cluster are obtained from a mosaic of XMM-Newton observations in the scale range between a resolution of 20 kpc and an extent of 2.8 Mpc. A Fourier analysis of the data reveals the…

天体物理学 · 物理学 2009-11-10 P. Schuecker , A. Finoguenov , F. Miniati , H. Boehringer , U. G. Briel

The pulse profile of pulsar gives geometric information about pulsar's radiation model. After investigating the pulse profiles of PSR B1642-03 and PSR B0950+08, we calculate the ratios of beam width and the emission height between different…

天体物理学 · 物理学 2007-05-23 X. H. Cui , K. J. Lee , G. J. Qiao , Y. L. Yue , R. X. Xu , H. G. Wang

We report the discovery of fast, frequency-dependent intensity variations from the scintillating intra-day variable quasar J1819+3845 at a wavelength of 21cm which resemble diffractive interstellar scintillations observed in pulsars. The…

天体物理学 · 物理学 2009-11-11 Jean-Pierre Macquart , Ger de Bruyn

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…

高能天体物理现象 · 物理学 2024-07-26 Jitendra Salal , Shriharsh P. Tendulkar , Visweshwar Ram Marthi

We present a study of the spectral properties of 441 pulsars observed with the Parkes radio telescope near the centre frequencies of 728, 1382 and 3100 MHz. The observations at 728 and 3100 MHz were conducted simultaneously using the…

高能天体物理现象 · 物理学 2018-03-30 F. Jankowski , W. van Straten , E. F. Keane , M. Bailes , E. Barr , S. Johnston , M. Kerr

The statistical properties of interstellar turbulence are studied by means of three-dimensional high-resolution HD and MHD simulations of a SN-driven ISM. It is found that the longitudinal and transverse turbulent length scales have time…

天体物理学 · 物理学 2017-08-23 Miguel A. de Avillez , Dieter Breitschwerdt

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…

We present simulations of scattering phenomena which are important in pulsar observations, but which are analytically intractable. The simulation code, which has also been used for solar wind and atmospheric scattering problems, is…

星系天体物理 · 物理学 2015-05-19 W. A. Coles , B. J. Rickett , J. J. Gao , G. Hobbs , J. P. W. Verbiest

Measurements of average pulse profiles made with a single linear polarization over the range 41-112 MHz are presented for PSR B0950+08. We show that the observed variable structure of the pulse profiles is a result of Faraday sinusoidal…

天体物理学 · 物理学 2009-11-10 T. V. Shabanova , Yu. P. Shitov

Observations of radio signals from distant pulsars provide a valuable tool for investigation of interstellar turbulence. The time-shapes of the signals are the result of pulse broadening by the fluctuating electron density in the…

天体物理学 · 物理学 2007-05-23 Stanislav Boldyrev , Carl R. Gwinn

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…

天体物理学 · 物理学 2009-10-31 N. D. Ramesh Bhat , A. Pramesh Rao , Yashwant Gupta

We present the analysis of time-resolved spectroscopy of the pulsating sdB star PG1605+072. From our main observing run of 16 nights we have detected velocity variations at 5 frequencies that correspond to those found in photometry. Based…

天体物理学 · 物理学 2009-11-07 S. J. O'Toole , T. R. Bedding , H. Kjeldsen , T. H. Dall , D. Stello

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

Interstellar radio wave scattering leads to flux density fluctuations and pulse broadening of pulsar signals. However, Galactic distribution and the structure of the scattering medium are still poorly understood. Pulsar pulse broadening…

星系天体物理 · 物理学 2023-12-19 Qiuyi He , Xun Shi