Radio-source structure in astrometric and geodetic very long baseline interferometry
- JPL, Pasadena, CA (USA) Institut Geographique National, Saint Mande (France)
An algorithm to calculate source structure corrections for bandwidth synthesis delays and delay rates is used to refer the position of extragalacitc radio sources to a specific feature of each source's morphology. The delay and delay rate are obtained from VBLI observations. The algorithm and its theoretical basis are described, and simulations for a simple two-component source are discussed. VLBI data for the complex radio source NRAO 140 are analyzed. For this source, structure corrections are calculated with maps from three different VLBI imaging techniques: the hybrid-CLEAN algorithm, the maximum entropy method, and model fitting. The calculated structure corrections are compared with brightness distributions to the actual data. The results are used to map NRAO 140. It is found that the CLEAN map produces the most accurate structure corrections. 27 refs.
- OSTI ID:
- 6806767
- Journal Information:
- Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 99; ISSN 0004-6256; ISSN ANJOA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALGORITHMS
BRIGHTNESS
CALCULATION METHODS
COMPARATIVE EVALUATIONS
COORDINATES
COSMIC RADIO SOURCES
GEODESY
INTERFEROMETRY
MATHEMATICAL LOGIC
MATHEMATICAL MODELS
MORPHOLOGY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
TIME DELAY