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Low-frequency variability of pulsars

Blandford, Roger and Narayan, Ramesh (1985) Low-frequency variability of pulsars. Monthly Notices of the Royal Astronomical Society, 213 (3). pp. 591-611. ISSN 0035-8711.

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Several recent observational and theoretical investigations have suggested that long-wavelength (⁠≲ 10^(14) cm⁠) density fluctuations in the interstellar medium may have a major influence on observations of pulsars and extragalactic radio sources. These long-wavelength fluctuations are responsible for refractive focusing (in contrast to the diffractive scintillation which is conventionally attributed to shorter wavelength fluctuations), and may cause the monthly to annual variations in pulsar flux densities observed at low frequency. Fluctuations in the angular sizes, pulse arrival times and pulse widths of pulsars should also be observable and should be cross-correlated with the flux density variations. The magnitude of these correlations, and their dependence upon the time lag and the observing wavelength, for different power-law spectra of density fluctuations are estimated. It appears that if the flux variability is interstellar in origin, then the spectrum must have a somewhat steeper logarithmic slope that the value (∼11/3) given by the standard ‘Kolmogorov’ spectrum. Sensitive observations on selected pulsars will be able to confirm the importance of refractive effects in the interstellar medium and also determine the slope of the density fluctuation spectrum.

Item Type:Article
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URLURL TypeDescription
Blandford, Roger0000-0002-1854-5506
Narayan, Ramesh0000-0002-1919-2730
Additional Information:© 1985 Royal Astronomical Society. Provided by the NASA Astrophysics Data System. Accepted 1984 November 6. Received 1984 November 6; in original form 1984 July 13. We are indebted to many colleagues, notably J. Armstrong, J. Cordes, J. Goodman, A. Readhead, R. Romani and J. Taylor, for invaluable discussions. We thank B. J. Rickett for detailed comments on the manuscript. Support by the National Science Foundation under grant AST 82-13001 and the Alfred P. Sloan Foundation is gratefully acknowledged.
Funding AgencyGrant Number
NSFAST 82-13001
Alfred P. Sloan FoundationUNSPECIFIED
Issue or Number:3
Record Number:CaltechAUTHORS:20190523-125439472
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Official Citation:Roger Blandford, Ramesh Narayan, Low-frequency variability of pulsars, Monthly Notices of the Royal Astronomical Society, Volume 213, Issue 3, 1 April 1985, Pages 591–611,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95756
Deposited By: George Porter
Deposited On:23 May 2019 20:02
Last Modified:03 Oct 2019 21:16

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