Decoherence in LOFAR-VLBI beamforming

Bonnassieux, Etienne; Edge, Alastair; Morabito, Leah; Bonafede, Annalisa

Abstract

We show that the use of a superstation (a phased array created using multiple stations of an interferometric array) created in post-processing for LOFAR-VLBI observations introduces a direction-dependent loss of signal in the image. We show this effect using simulations and real data. Using the RIME formalism, we characterise it fully, and give limits under which this signal loss is negligible. Finally, we show that we are able to fully predict this effect. We close with guidelines for interferometric observers to avoid this effect in their observations, and a discussion of techniques which could limit this effect or do away with it entirely. The latter in particular will be relevant to the SKA should its long baselines be used to their fullest potential.

Citation

Bonnassieux, E., Edge, A., Morabito, L., & Bonafede, A. (2020). Decoherence in LOFAR-VLBI beamforming. Astronomy & Astrophysics, 637, Article A51. https://doi.org/10.1051/0004-6361/202037486

• Journal Article Type: Article
• Acceptance Date: Mar 13, 2020
• Online Publication Date: May 13, 2020
• Publication Date: 2020-05
• Deposit Date: Jun 17, 2020
• Publicly Available Date: Jun 17, 2020
• Journal: Astronomy and astrophysics.
• Print ISSN: 0004-6361
• Electronic ISSN: 1432-0746
• Publisher: EDP Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 637
• Article Number: A51
• DOI: https://doi.org/10.1051/0004-6361/202037486
• Public URL: https://durham-repository.worktribe.com/output/1268598