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We show the results of our analysis of the pulse broadening phenomenon in 25 pulsars at several frequencies using the data gathered with GMRT and Effelsberg radiotelescopes. Twenty two of these pulsars were not studied in that regard before…

高能天体物理现象 · 物理学 2015-06-16 Wojciech Lewandowski , Marta Dembska , Jaroslaw Kijak , Magdalena Kowalinska

We present the results of the multi-frequency scatter time measurements for ten radio pulsars that were relatively less studied in this regard. The observations were performed using the Giant Meterwave Radio Telescope at the observing…

高能天体物理现象 · 物理学 2015-10-21 Wojciech Lewandowski , Karolina Rozko , Jaroslaw Kijak , Bhaswati Bhattacharyya , Jayanta Roy

We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the…

高能天体物理现象 · 物理学 2019-06-26 M. A. Krishnakumar , Yogesh Maan , Bhal Chandra Joshi , P. K. Manoharan

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

We present multi-wavelength scatter broadening observations of 47 pulsars, made with the Giant Metre-wave Radio Telescope (GMRT), Ooty Radio Telescope (ORT) and Long Wavelength Array (LWA). The GMRT observations have been made in the phased…

高能天体物理现象 · 物理学 2017-09-13 M. A. Krishnakumar , Bhal Chandra Joshi , P. K. Manoharan

We present a robust approach to incorporating models for the time-variable broadening of the pulse profile due to scattering in the ionized interstellar medium into profile-domain pulsar timing analysis. We use this approach to…

天体物理仪器与方法 · 物理学 2017-04-12 L. Lentati , M. Kerr , S. Dai , R. M. Shannon , G. Hobbs , S. Oslowski

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…

天体物理学 · 物理学 2009-11-07 O. Loehmer , M. Kramer , D. Mitra , D. R. Lorimer , A. G. Lyne

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

In an earlier paper (Ahuja, et al, 2005), based on simultaneous multi-frequency observations with the Giant Metrewave Radio Telescope (GMRT), we reported the variation of pulsar dispersion measures (DMs) with frequency. A few different…

天体物理学 · 物理学 2008-11-26 Amrit Lal Ahuja , Dipanjan Mitra , Yashwant Gupta

Radio pulses from pulsars are affected by plasma dispersion, which results in a frequency-dependent propagation delay. Variations in the magnitude of this effect lead to an additional source of red noise in pulsar timing experiments,…

The turbulent ionized interstellar medium diffracts radio waves and makes them propagate in multiple paths. The pulse-broadening observed at low frequencies results from the scattering effect of interstellar clouds of ionized gas. During…

高能天体物理现象 · 物理学 2025-06-18 W. C. Jing , J. L. Han , C. Wang , P. F. Wang , T. Wang , N. N. Cai , J. Xu , Z. L. Yang , D. J. Zhou , Yi Yan , W. Q. Su , X. Y. Gao , L. Xie

In this work we adopted a CLEAN-based method to determine the scatter time, $\tau$, from archived pulsar profiles under both the thin screen and uniform medium scattering models and to calculate the scatter time frequency scale index…

高能天体物理现象 · 物理学 2017-01-23 Jr-Wei Tsai , John H. Simonetti , Michael Kavic

This paper describes a comprehensive measurement model for the error budget of pulse arrival times with emphasis on intrinsic pulse jitterand plasma propagation effects (particularly interstellar scattering), which are stochastic in time…

天体物理仪器与方法 · 物理学 2010-10-20 J. M. Cordes , R. M. Shannon

Interstellar scattering causes pulsar profiles to grow asymmetrically, thus affecting the pulsar timing residuals, and is strongest at lower frequencies. Different Interstellar medium models predict different frequency ($\nu$) and…

高能天体物理现象 · 物理学 2019-05-01 Karishma Bansal , G. B. Taylor , Kevin Stovall , Jayce Dowell

We have measured the scattering timescale, $\tau$, and the scattering spectral index, $\alpha$, for 84 single-component pulsars. Observations were carried out with the MeerKAT telescope as part of the Thousand-Pulsar-Array programme in the…

In this paper we report multi-frequency measurements of pulse broadening times (tau_d) for nine medium dispersion measure (DM $\approx 150-400$ pc cm$^{-3}$) pulsars observed over a wide frequency range. The low frequency data at 243, 325…

天体物理学 · 物理学 2009-11-10 O. Loehmer , D. Mitra , Y. Gupta , M. Kramer , A. Ahuja

We analyse dispersion measure (DM) variations in six years of radio observations of more than 160 young pulsars, all gamma ray candidates for the Fermi gamma ray telescope mostly located close to the Galactic plane. DMs were fit across 256…

星系天体物理 · 物理学 2015-06-16 E. Petroff , M. J. Keith , S. Johnston , W. van Straten , R. M. Shannon

We analyze the frequency dependence of the dispersion measure (DM), the column density of free electrons to a pulsar, caused by multipath scattering from small scale electron-density fluctuations. The DM is slightly different along each…

天体物理仪器与方法 · 物理学 2016-01-21 J. M. Cordes , R. M. Shannon , D. R. Stinebring

We have made observations of 98 low-Galactic-latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305-m Arecibo telescope at four radio frequencies…

天体物理学 · 物理学 2009-11-10 N. D. Ramesh Bhat , James M. Cordes , Fernando Camilo , David J. Nice , Duncan R. Lorimer

The survey of northern hemisphere were made at a frequency of 111 MHz. The total accumulation time at each point of the sky was at least one hour. 75 sources of pulse emission were detected. More then 80% of these sources are known pulsars…

高能天体物理现象 · 物理学 2022-04-12 S. A. Tyul'bashev , M. A. Kitaeva , S. V. Logvinenko , G. E. Tyul'basheva
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