Title:	Closure invariants for polarised radio interferometric observations: A graph theoretical approach
Authors:	Kumar, Vinay Nityananda, Rajaram Samuel, Joseph
Keywords:	Aperture synthesis polarisation closure invariants
Issue Date:	18-Aug-2025
Publisher:	Springer for Indian Academy of Sciences
Citation:	Journal of Astrophysics and Astronomy, 2025, Vol.46, Article No. 56
Abstract:	Aperture synthesis observations in radio wavelengths with full polarisation, have long been used to study the magnetic fields of synchrotron-emitting sources. Recently proposed closure invariants – quantities immune to antenna-specific signal corruptions – give us a powerful method for extracting information from measured visibilities, which are corrupted by antenna and polarisation-dependent gains. This paper extends a formalism developed earlier for complete graphs (where all visibilities are available) 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.
Description:	Open Access
URI:	http://hdl.handle.net/2289/8438
Alternative Location:	https://arxiv.org/abs/2407.00583 https://doi.org/10.1007/s12036-025-10081-9 https://ui.adsabs.harvard.edu/abs/2024arXiv240700583K/abstract
Copyright:	2025 Indian Academy of Sciences
Appears in Collections:	Research Papers (TP)

Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.