Widening the field-of-view of Very Long Baseline Interferometric surveys through advanced calibration techniques

dc.contributor.advisorRadcliffe, Jack F.
dc.contributor.emailll3w3llyncoetzer@gmail.com
dc.contributor.postgraduateCoetzer, Llewellyn Victor
dc.date.accessioned2025-06-25T14:39:04Z
dc.date.available2025-06-25T14:39:04Z
dc.date.created2025-09
dc.date.issued2025-05
dc.descriptionDissertation (MSc (Physics))--University of Pretoria, 2025.
dc.description.abstractVery long baseline interferometry (VLBI) is a vital tool in astronomy that unlocks extremely high resolutions with high sensitivity. The fields of view (FoVs) of VLBI observations historically were limited by bandwidth and time smearing, as well as signal attenuation experienced by the array elements due to their primary beams. Technological upgrades and improved correlation and calibration techniques have largely eliminated smearing, leaving the primary beams as the last major FoV restriction. In this thesis, we derive primary beam models for a large subset of antennas in the European VLBI Network (EVN) and enhanced Multi-Element Radio Linked Interferometer Network (e-MERLIN) using an observation scheme similar to out-of-focus holography (OOF). These models are also applied to a wide-field observation of the Hubble Deep Field-North (HDFN) to test their efficacy in removing beam-related attenuation. Obtaining accurate primary beam models of the antennas in VLBI networks would allow for wide-field observations’ development to accelerate and unlock many new facets of science, including active galactic nuclei (AGN) surveys, AGN feedback studies, gravitational lens surveys, and interstellar medium density studies, to only mention a few. In this project, we also face the additional challenge of modelling heterogeneous arrays, meaning that different primary beams are present in the data.
dc.description.availabilityUnrestricted
dc.description.degreeMSc (Physics)
dc.description.departmentPhysics
dc.description.facultyFaculty of Natural and Agricultural Sciences
dc.identifier.citation*
dc.identifier.doihttps://doi.org/10.25403/UPresearchdata.29120099
dc.identifier.otherS2025
dc.identifier.urihttp://hdl.handle.net/2263/103003
dc.identifier.uriDOI: https://doi.org/10.25403/UPresearchdata.29120099.v1en
dc.language.isoen
dc.publisherUniversity of Pretoria
dc.rights© 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subjectUCTD
dc.subjectInstrumentation: interferometers
dc.subjectMethods: analytical
dc.subjectMethods: numerical
dc.subjectTechniques: interferometric
dc.titleWidening the field-of-view of Very Long Baseline Interferometric surveys through advanced calibration techniques
dc.typeDissertation

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