Projects per year
Abstract
Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images.
Original language | English |
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Article number | 5 |
Number of pages | 19 |
Journal | Astronomy and Astrophysics |
Volume | 636 |
DOIs | |
Publication status | Published - 1 Apr 2020 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Atmospheric effects
- Black hole physics
- Galaxies: nuclei
- Techniques: high angular resolution
- Techniques: interferometric
- Telescopes
Fingerprint
Dive into the research topics of 'SYMBA: An end-to-end VLBI synthetic data generation pipeline: Simulating Event Horizon Telescope observations of M 87'. Together they form a unique fingerprint.Projects
- 5 Finished
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Physics of Black Hole-Powered Jets
Savolainen, T. (Principal investigator) & Chamani Velasco, W. (Project Member)
01/09/2017 → 31/08/2019
Project: Academy of Finland: Other research funding
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Physics of Black Hole-Powered Jets
Savolainen, T. (Principal investigator)
01/01/2016 → 31/08/2019
Project: Academy of Finland: Other research funding
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Physics of Black Hole-Powered Jets
Savolainen, T. (Principal investigator), Chamani Velasco, W. (Project Member) & Kiehlmann, S. (Project Member)
01/01/2016 → 31/08/2017
Project: Academy of Finland: Other research funding
Equipment
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Metsähovi Radio Observatory
Tammi, J. (Manager)
School of Electrical EngineeringFacility/equipment: Facility