Closure invariants for polarised radio interferometric observations: a graph theoretical approach
Abstract
Aperture synthesis observations with full polarisation have long been used to study the magnetic fields of synchrotron emitting sources. Recently proposed closure invariants give us a powerful method for extracting information from measured visibilities which are corrupted by antenna and polarisation dependent gains. In this paper, a formalism developed earlier for complete graphs (where all visibilities are available) is extended to incomplete graphs. The formalism provides a complete and independent set of closure invariants from the measured visibilities in a general situation where not all visibilities are available. We then show in a simulated, quasi-realistic case that the invariants developed here contain usable information even in the presence of noise.
- Publication:
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arXiv e-prints
- Pub Date:
- June 2024
- DOI:
- 10.48550/arXiv.2407.00583
- arXiv:
- arXiv:2407.00583
- Bibcode:
- 2024arXiv240700583K
- Keywords:
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- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 4 pages, 4 figures