Abstract: | 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
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 comparison with observational data. 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. We used SYMBA to create synthetic
observations for the Event Horizon Telescope (EHT), a mm 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. Based on two example general
relativistic magnetohydrodynamics (GRMHD) model images of M87, we performed
case studies to assess the attainable image quality with the current and future
EHT array for different weather conditions. The results 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
the input models can be recovered robustly after performing calibration steps.
With the planned addition of new stations to the EHT array, 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. |