Diffractive Interstellar Scintillation Timescales and Velocities

Cordes, J. M.; Rickett, B. J.

doi:10.1086/306358

Cited by 227 publications

(282 citation statements)

References 39 publications

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“…1 for an example of the extreme form of this variation: the different parts of the same pulse show different scattering effects, imparting a significant structure to the pulse. In their work on DISS, Cordes & Rickett (1998) emphasise that considering the 1/e time equal to τ s is only valid for a thin screen and does not always hold. In light of the limited validity in interpreting the 1/e time and the spread in the values of scatter times found in our analysis, we suggest that the scattering in the direction of Crab pulsar cannot be modelled by single thin screen.…”

Section: Single-pulse Scatteringmentioning

confidence: 99%

Giant pulses from the Crab pulsar

Karuppusamy

Stappers

Straten³

2010

A&A

109

111

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The Crab pulsar is well-known for its anomalous giant radio pulse emission. Past studies have concentrated only on the very bright pulses or were insensitive to the faint end of the giant pulse luminosity distribution. With our new instrumentation offering a large bandwidth and high time resolution combined with the narrow radio beam of the Westerbork Synthesis Radio Telescope (WSRT), we seek to probe the weak giant pulse emission regime. The WSRT was used in a phased array mode, resolving a large fraction of the Crab nebula. The resulting pulsar signal was recorded using the PuMa II pulsar backend and then coherently dedispersed and searched for giant pulse emission. After careful flux calibration, the data were analysed to study the giant pulse properties. The analysis includes the distributions of the measured pulse widths, intensities, energies, and scattering times. The weak giant pulses are shown to form a separate part of the intensity distribution. The large number of giant pulses detected were used to analyse scattering and scintillation in giant pulses. We report for the first time the detection of giant pulse emission at both the main-and interpulse phases within a single rotation period. The rate of detection is consistent with the appearance of pulses at either pulse phase as being independent. These pulse pairs were used to examine the scintillation timescales within a single pulse period.

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Section: Single-pulse Scatteringmentioning

confidence: 99%

Giant pulses from the Crab pulsar

Karuppusamy

Stappers

Straten³

2010

A&A

109

111

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“…Unlike DISS effects, there are several aspects of RISS phenomena that remain to be well understood (e.g. Rickett 1990;Cordes & Rickett 1998).…”

Section: Introductionmentioning

confidence: 99%

A study of the long-term flux density variation of PSRs B0329+54 and B1508+55

Esamdin

Zhou

2004

A&A

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Abstract.We have observed the flux densities of PSRs B0329+54 and B1508+55 for 460 days at 327 MHz using the 25 m telescope of NAOC Urumqi Observatory. The flux density time series and the corresponding structure functions are presented. Our observational results at 327 MHz and other observations at 74 MHz and 610 MHz are compared with the predictions of the refractive scintillation theory. The frequency dependence of the refractive scintillation parameters for PSR B0329+54 has been investigated. The results show that the long-term flux density modulations of PSR B0329+54 at the three frequencies are best described by a Kolmogorov spectrum for electron density inhomogeneities. For PSR B1508+55, we suggest that the spectrum of the electron density fluctuation has a power exponent β < 4.

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“…Therefore, σ = W 10, int / √ 8 ln 10. The temporal pulse broadening is parametrised with the timescale τ d , defined as the first moment of the broadening function, roughly a one-sided exponential, determined by deconvolving the intrinsic and measured pulse shapes (see for instance Cordes & Lazio 2002;Cordes & Rickett 1998). We effectively considered a one-sided exponential for the pulse broadening Hence, τ d is the width of the pulse to 1/e of the maximum pulse amplitude if the intrinsic pulse shape is a delta function.…”

Section: Discussionmentioning

confidence: 99%

“…The ISM electron density variations cause a multipath scattering reflected in a temporal broadening of the pulses at high DMs and low frequencies (see for instance Cordes & Rickett 1998;…”

Section: Appendix A: Pulse Width and Broadeningmentioning

confidence: 99%

Search for radio pulsations in LS I +61 303

Cañellas

Joshi

Paredes

et al. 2012

A&A

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Context. LS I +61 303 is a member of the select group of gamma-ray binaries: galactic binary systems that contain a massive star and a compact object, show a changing milliarcsecond morphology and a similar broad spectral energy distribution (SED) that peaks at MeV-TeV energies and is modulated by the orbital motion. The nature of the compact object is unclear in LS I +61 303, LS 5039 and HESS J0632+057, whereas PSR B1259-63 harbours a 47.74 ms radio pulsar. Aims. A scenario in which a young pulsar wind interacts with the stellar wind has been proposed to explain the very high energy (VHE, E > 100 GeV) gamma-ray emission detected from LS I +61 303, although no pulses have been reported from this system at any wavelength. We aim to find evidence of the pulsar nature of the compact object. Methods. We performed phased array observations with the Giant Metrewave Radio Telescope at 1280 MHz centred at phase 0.54. Simultaneous data from the multi-bit phased array back-end with a sampling time of t samp = 128 μs and from the polarimeter back-end with t samp = 256 μs where taken. Results. No pulses have been found in the data set, with a minimum detectable mean flux density of ∼0.38 mJy at 8-σ level for the pulsed emission from a putative pulsar with period P > 2 ms and duty cycle D = 10% in the direction of LS I +61 303. Conclusions. The detection of posible radio pulsations will require deep and sensitive observations at frequencies ∼0.5-5 GHz and orbital phases 0.6−0.7. However, it may be unfeasible to detect pulses if the putative pulsar is not beamed at the Earth or if there is a strong absorption within the binary system.

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Diffractive Interstellar Scintillation Timescales and Velocities

Cited by 227 publications

References 39 publications

Giant pulses from the Crab pulsar

Giant pulses from the Crab pulsar

A study of the long-term flux density variation of PSRs B0329+54 and B1508+55

Search for radio pulsations in LS I +61 303

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