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Comparison of pulsar positions from timing and very long baseline astrometry

Wang, J. B. and Ravi, V. (2017) Comparison of pulsar positions from timing and very long baseline astrometry. Monthly Notices of the Royal Astronomical Society, 469 (1). pp. 425-434. ISSN 0035-8711. doi:10.1093/mnras/stx837.

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Pulsar positions can be measured with high precision using both pulsar timing methods and very long baseline interferometry (VLBI). Pulsar timing positions are referenced to a solar-system ephemeris, whereas VLBI positions are referenced to distant quasars. Here, we compare pulsar positions from published VLBI measurements with those obtained from pulsar timing data from the Nanshan and Parkes radio telescopes in order to relate the two reference frames. We find that the timing positions differ significantly from the VLBI positions (and also differ between different ephemerides). A statistically significant change in the obliquity of the ecliptic of 2.16 ± 0.33 mas is found for the JPL ephemeris DE405, but no significant rotation is found in subsequent JPL ephemerides. The accuracy with which we can relate the two frames is limited by the current uncertainties in the VLBI reference source positions and in matching the pulsars to their reference source. Not only do the timing positions depend on the ephemeris used in computing them, but also different segments of the timing data lead to varying position estimates. These variations are mostly common to all ephemerides, but slight changes are seen at the 10 μas level between ephemerides.

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Ravi, V.0000-0002-7252-5485
Additional Information:© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 March 31. Received 2017 March 27; in original form 2017 February 12. Published: 05 April 2017. The Parkes radio telescope is part of the Australia Telescope, which is funded by the Commonwealth of Australia for operation as a National Facility managed by the Commonwealth Scientific and Industrial Research Organization (CSIRO). This work is supported by West Light Foundation of Chinese Academy of Sciences (No. XBBS201322) and National Natural Science Foundation of China (Nos. 11403086, U1431107, 11373006), the Strategic Priority Research Programme (B) of the Chinese Academy of Sciences (No. XDB23010200) and GH acknowledge support from the Australian Research Council (ARC) Future Fellowship. We acknowledge comments on early drafts of the manuscript from Dr A. Deller. This work used the astronomy & astrophysics package for MATLAB (Ofek 2014).
Funding AgencyGrant Number
Commonwealth of AustraliaUNSPECIFIED
Chinese Academy of SciencesXBBS201322
National Natural Science Foundation of China11403086
National Natural Science Foundation of ChinaU1431107
National Natural Science Foundation of China11373006
West Light FoundationXDB23010200
Australian Research CouncilUNSPECIFIED
Subject Keywords:methods: data analysis – techniques: interferometric – astrometry – reference systems – pulsars: general
Issue or Number:1
Record Number:CaltechAUTHORS:20170627-103854248
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Official Citation:J. B. Wang, W. A. Coles, G. Hobbs, R. M. Shannon, R. N. Manchester, M. Kerr, J. P. Yuan, N. Wang, M. Bailes, N. D. R. Bhat, S. Dai, J. Dempsey, M. J. Keith, P. D. Lasky, Y. Levin, S. Osłowski, V. Ravi, D. J. Reardon, P. A. Rosado, C. J. Russell, R. Spiewak, W. van Straten, L. Toomey, L. Wen, X.-P. You, X.-J. Zhu; Comparison of pulsar positions from timing and very long baseline astrometry. Mon Not R Astron Soc 2017; 469 (1): 425-434. doi: 10.1093/mnras/stx837
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78608
Deposited By: Tony Diaz
Deposited On:27 Jun 2017 17:52
Last Modified:15 Nov 2021 17:41

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