Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/88594

Title

Scattering of pulsar radio emission by the interstellar plasma

Author(s)

Coles, W. A.;  Rickett, B. J.;  Gao, J. J.;  Hobbs, G.;  Verbiest, J. P. W.

Abstract

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.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Astrophysical Journal, Vol. 717, no. 2 (Jul 2010), pp. 1206-1221

Publication year

2010

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

ISM;  Pulsars;  Scattering

Publisher

Institute of Physics Publishing

ISSN

0004-637X

Publisher URL

http://dx.doi.org/10.1088/0004-637X/717/2/1206

Copyright

Copyright © 2010 The American Astronomical Society. All rights reserved.

Additional information

The authors acknowledge support from the the NSF under grant AST-0507713, the Parkes Observatory and the Astronomical Society of Australia.

Peer reviewed