SCATTERING OF PULSAR RADIO EMISSION BY THE INTERSTELLAR PLASMA
- Department of Electrical Engineering and Computer Sciences, University of California, San Diego, La Jolla, CA 92093 (United States)
- Australia Telescope National Facility, CSIRO, P.O. Box 76, Epping, NSW 1710 (Australia)
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218 Hawthorn, VIC 3122 (Australia)
We present simulations of scattering phenomena which are important in pulsar observations, but which are analytically intractable. The simulation code, which has also been used for solar wind and atmospheric scattering problems, is available from the authors. These simulations reveal an unexpectedly important role of dispersion in combination with refraction. We demonstrate the effect of analyzing observations which are shorter than the refractive scale. We examine time-of-arrival fluctuations in detail: showing their correlation with intensity and dispersion measure, providing a heuristic model from which one can estimate their contribution to pulsar timing observations, and showing that much of the effect can be corrected making use of measured intensity and dispersion. Finally, we analyze observations of the millisecond pulsar J0437-4715, made with the Parkes radio telescope, that show timing fluctuations which are correlated with intensity. We demonstrate that these timing fluctuations can be corrected, but we find that they are much larger than would be expected from scattering in a homogeneous turbulent plasma with isotropic density fluctuations. We do not have an explanation for these timing fluctuations.
- OSTI ID:
- 21455185
- Journal Information:
- Astrophysical Journal, Vol. 717, Issue 2; Other Information: DOI: 10.1088/0004-637X/717/2/1206; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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