- Title
- A pilot wide-field VLBI survey of the GOODS-North field
- Creator
- Akoto-Danso, Alexander
- ThesisAdvisor
- Deane, Roger
- ThesisAdvisor
- Smirnov, Oleg
- ThesisAdvisor
- Bernardi, Gianni
- Subject
- Radio astronomy
- Subject
- Very long baseline interferometry
- Subject
- Radio interometers
- Subject
- Imaging systems in astronomy
- Subject
- Hubble Space Telescope (Spacecraft) -- Observations
- Date
- 2019
- Type
- text
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10962/72296
- Identifier
- vital:30027
- Description
- Very Long Baseline Interferometry (VLBI) has significant advantages in disentangling active galactic nuclei (AGN) from star formation, particularly at intermediate to high-redshift due to its high angular resolution and insensitivity to dust. Surveys using VLBI arrays are only just becoming practical over wide areas with numerous developments and innovations (such as multi-phase centre techniques) in observation and data analysis techniques. However, fully automated pipelines for VLBI data analysis are based on old software packages and are unable to incorporate new calibration and imaging algorithms. In this work, the researcher developed a pipeline for VLBI data analysis which integrates a recent wide-field imaging algorithm, RFI excision, and a purpose-built source finding algorithm specifically developed for the 64kx64k wide-field VLBI images. The researcher used this novel pipeline to process 6% (~ 9 arcmin2 of the total 160 arcmin2) of the data from the CANDELS GOODS- North extragalactic field at 1.6 GHz. The milli-arcsec scale images have an average rms of a ~ 10 uJy/beam. Forty four (44) candidate sources were detected, most of which are at sub-mJy flux densities, having brightness temperatures and luminosities of >5x105 K and >6x1021 W Hz-1 respectively. This work demonstrates that automated post-processing pipelines for wide-field, uniform sensitivity VLBI surveys are feasible and indeed made more efficient with new software, wide-field imaging algorithms and more purpose-built source- finders. This broadens the discovery space for future wide-field surveys with upcoming arrays such as the African VLBI Network (AVN), MeerKAT and the Square Kilometre Array (SKA).
- Format
- 136 pages, pdf
- Publisher
- Rhodes University, Faculty of Science, Physics and Electronics
- Language
- English
- Rights
- Akoto-Danso, Alexander
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