Incorporating the extra coverage and time window from these sites, the authors reproduced the plasma flow in the quiescent state of Sgr A* using general relativistic magnetohydrodynamic simulations (SANE model) under the same antenna and weather parameters of observations taken in 2017. To reproduce the flares, La Bella et al. used a simulated Gaussian flaring feature with the correct orbiting period to produce hotspot synthetic data. Movie reconstructions from these data were made using standard EHT dynamical imaging methods and compared with models of the accretion flow and jet. The inclusion of these two sites improves the resolution and better constrains the size of source. For the ‘Eastern array’ — the current EHT configuration until ~ 9.5 hours ut — the African stations offer a time window of 7 hours, thereby increasing by a factor of 4 the time available for dynamical imaging, which is sufficient for producing high-fidelity movies for observing motions within the accretion disk. Without the two extra sites, the synthetic data with the Eastern array alone cannot reproduce the black hole shadow.
Work on the African Millimetre Telescope is underway, following an ERC grant of €14m. The first millimetre wave telescope in Africa will be at the same latitude as ALMA in Chile, which significantly increases the snapshot coverage during the first half of an observing night (the figure shows the added baselines both east–west and north–south). Based on the work of La Bella and co-workers, we can soon expect movies of the black hole at the centre of the Milky Way galaxy, and of other sources, particularly in the southern sky.
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