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On the estimation of a celestial reference frame in the presence of source structure
journal contribution
posted on 2023-05-18, 16:08 authored by Lucia McCallumLucia McCallum, Stanislav ShabalaStanislav Shabala, Jamie McCallumJamie McCallum, Krasna, H, Petrachenko, B, Rastorgueva-Foi, E, James LovellJames LovellThe spatial structure of sources making up the celestial reference frame (CRF) at radio frequencies is a systematic error source in very long baseline interferometry (VLBI) measurements. Using simulations, we investigate the effects of source structure on the CRF, determined by the actual observational programme of the International VLBI Service for Geodesy and Astrometry. This is done using the source structure simulator of the Vienna VLBI Software. Applying various mock two-component source models, systematic displacements of 10–80 μas in median source position offsets are found. These offsets are predominantly aligned with the direction of the jet. The simulations further show that slight changes in the source model can significantly change the estimated positions. We finally present a new parametrization of source positions in the analysis, namely along the jet direction and perpendicular to it, allowing us to significantly mitigate the effects of source structure on an estimated CRF.
History
Publication title
Monthly Notices of the Royal Astronomical SocietyVolume
455Pagination
343-356ISSN
0035-8711Department/School
School of Natural SciencesPublisher
Blackwell Publishing LtdPlace of publication
Oxford, EnglandRights statement
Copyright 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Repository Status
- Open