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Title

Rotation measure variations for 20 millisecond pulsars

Author(s)

Yan, W. M.;  Manchester, R. N.;  Hobbs, G.;  van Straten, W.;  Reynolds, J. E.;  Wang, N.;  Bailes, M.;  Bhat, N. D. R.;  Burke-Spolaor, S.;  Champion, D. J.;  Chaudhary, A.;  Coles, W. A.;  Hotan, A. W.;  Khoo, J.;  Oslowski, S.;  Sarkissian, J. M.;  Yardley, D. R. B.

Abstract

We report on variations in the mean position angle of the 20 millisecond pulsars being observed as part of the Parkes Pulsar Timing Array (PPTA) project. It is found that the observed variations are dominated by changes in the Faraday rotation occurring in the Earth's ionosphere. Two ionospheric models are used to correct for the ionospheric contribution and it is found that one based on the International Reference Ionosphere gave the best results. Little or no significant long-term variation in interstellar RM was found with limits typically about 0.1 rad m-2 yr-1 in absolute value. In a few cases, apparently significant RM variations over timescales of a few 100 days or more were seen. These are unlikely to be due to localised magnetised regions crossing the line of sight since the implied magnetic fields are too high. Most probably they are statistical fluctuations due to random spatial and temporal variations in the interstellar electron density and magnetic field along the line of sight.

Publication type

Journal article

Research centre

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

Source

Astrophysics and Space Science, Vol. 335, no. 2 (Oct 2011), pp. 485-498

Publication year

2011

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Interstellar medium;  ISM;  Pulsars;  Radio continuum;  Rotation measure;  Stars

Publisher

Springer

ISSN

0004-640X

Publisher URL

http://dx.doi.org/10.1007/s10509-011-0756-0

Copyright

Copyright © Springer Science+Business Media B.V. 2011. The accepted manuscript of the paper is reproduced here in accordance with the copyright policy of the publisher. The definitive version of the publication is available at www.springer.com.

Full text

Peer reviewed