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Constraints on Interstellar Plasma Turbulence Spectrum from Pulsar Observations at the Ooty Radio Telescope

Published online by Cambridge University Press:  12 April 2016

N. D. Ramesh Bhat
Affiliation:
Max-Planck-Institut für Radioastronomie, Bonn, Germany
Yashwant Gupta
Affiliation:
National Centre for Radio Astrophysics, Pune, India
A. Pramesh Rao
Affiliation:
National Centre for Radio Astrophysics, Pune, India

Extract

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Refractive Interstellar Scintillation (RISS) effects on pulsar signals are powerful techniques for discriminating between different models that have been proposed for the power spectrum of plasma density fluctuations in the Interstellar Medium (ISM; e.g. Rickett 1990). The nature of the spectrum is considered to be a major input for understanding the underlying mechanism of interstellar plasma turbulence. Data from our long-term pulsar scintillation observations using the Ooty Radio Telescope (ORT) at 327 MHz are used to investigate the nature of the spectrum in the Local Interstellar Medium (LISM; region within ∼ 1 kpc of the Sun). Dynamic scintillation spectra were obtained for 18 pulsars in the DM range 3–35 pc cm−3 at ∼10–100 epochs spanning ∼100–1000 days during 1993–1995 (Bhat et al. 1999). From these observations, various scintillation properties and the ISM parameters are estimated with accuracies much better than that which has been possible from most earlier data. The time series of parameters, viz., decorrelation bandwidth (vd), scintillation time scale (τd) and the drift slope of intensity scintillation patterns, and pulsar flux density are used to study various observable effects of Interstellar Scintillation, based on which the spectral form is inferred over the spatial scale range ∼ 107 m to ∼ 1013 m.

Type
Part 8. Pulsars and the Interstellar Medium
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

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