Long-term intensity variations of 20 pulsars

LaBrecque, D. R.; Rankin, John; Cordes, J. M.

doi:10.1086/117198

Cited by 20 publications

(13 citation statements)

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“…Gupta et al (1993, hereafter GRC93) presented 400 days of flux density monitoring for nine nearby pulsars at 74 MHz. LaBrecque et al (1994) studied 20 pulsars at 430 MHz observed over a 4 yr span. Bhat et al (1999a) presented results of a project of dynamic-scintillation-spectra monitoring of 18 pulsars at 327 MHz during a 3 yr period.…”

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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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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“…Bhat & Gupta (2002) took a more detailed look at the distribution of scattering material toward Loop I and beyond. On the observational front, significant work has been done on the flux density monitoring LaBrecque et al 1994;Esamdin et al 2000) and the short timescale variations in dynamic spectra (Gupta et al 1994;Stinebring et al 1996;Wang et al 2001). It is concluded that the diffractive and refractive scintillation are caused by the same underlying scattering process.…”

Section: Introductionmentioning

confidence: 99%

Long-term flux density variations of pulsars: Theoretical structure functions and comparisons with observations

Zhou

Esamdin

2003

A&A

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Abstract. By means of the refractive interstellar scintillation theory (RISS), the flux density structure functions of PSRs B1642-03, B0736-40, B0740-28 and B0329+54 are calculated and compared with the observations at 610 MHz by Stinebring et al. (2000. The theoretical results are in good agreement with observations and the spectra of the electron density fluctuation are all consistent with the Kolmogorov spectra. The theoretical modulation indices m are comparatively less sensitive to the distance H from the observer to the scattering screen but critically depend on the scattering strength C 2 N . The structure function does not change remarkably with the variation of H if the scattering screen is closer to the pulsar than to the observer. The results in this paper indicate that the flux density variations observed for these four pulsars are due to a propagation effect (refractive scintillation), not to the intrinsic variability.

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“…The time-scale of the flux variations is predicted to increase as a positive power of the observing wavelength and the DM. Following Sieber's work and the theoretical predictions, there have been a number of new RISS studies of pulsar fluxes (Stinebring Sz Condon 1990, Rick-ett tgz , Kaspi & Stinebring 1992, Gupta et al 1993, LaBrecque et al 1994. The results tend to support an extended Kolmogorov power-law spectrum of interstellar plasma turbulence, with some modifications.…”

Section: Interstellar Turbulencementioning

confidence: 88%

Timing observations of southern pulsars - 1987 to 1991

D’Alessandro

McCulloch

King

et al. 1993

Monthly Notices of the Royal Astronomical Society

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Pulse arrival-time measurements made at frequencies near 670 and 800 MHz over a 7-year period have been used to study the timing behaviour of 45 southern pulsars. These measurements have resulted in more accurate estimates of the period, period derivative, position and dispersion measure of most of these pulsars. Changes in some of the dispersion measures have been detected and used to estimate the scale-sizes and electron densities of irregularities in the interstellar medium. The timing measurements also revealed distinct jumps in the rotation rate of five pulsars, most of which have not been reported elsewhere.Polarimetric data at 670 and 800 MHz are presented for eighteen of the more luminous pulsars. The integrated profiles display properties in general agreement with trends extrapolated from other frequencies. Rotation measures have been derived for these pulsars. Nine are more accurate than previous determinations, and two have changed since they were last measured. These changes suggest a dense, magnetised electron cloud has moved into or out of the line of sight.It has been confirmed that the level of pulsar timing noise is correlated with spin-down rates. Further analyses have revealed that, in most pulsars, the observed timing noise is due to a mixture of different kinds of activity, such as random walk processes, microjumps, and for one pulsar, free precession of the spin axis. The microjumps are characterised by a variety of signatures, involving both positive and negative changes in the rotation frequency and frequency derivative. The amplitudes of these microjumps form the tail-end of a continuous distribution of amplitudes extending down to microglitch level. An investigation of timing noise in the Vela pulsar has shown that the microactivity during the postglitch recovery period is dominated by microjumps in the rotation frequency and frequency derivative which occur every 30-40 days. This microactivity is also punctuated by less frequent events, such as large steps in the frequency derivative, discrete changes in the frequency second derivative, and in one isolated case, a small glitch. The above results have been discussed in terms of current theories of pulsar timing noise and it was found that no theoretical model, in isolation, is able to explain the range of observed timing activity in the pulsars studied.Power spectra of the pulsar timing residuals have been derived using a novel technique based on the CLEAN algorithm. Most of the spectra are well described by a single-or double-component power-law model. Some of these spectra can be interpreted in the context of one or more of the current timing noise models.

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Long-term intensity variations of 20 pulsars

Cited by 20 publications

References 0 publications

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

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

Long-term flux density variations of pulsars: Theoretical structure functions and comparisons with observations

Timing observations of southern pulsars - 1987 to 1991

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