Evaluation of South African Candidate Sites for an Expanded Event Horizon Telescope

Abstract

Global expansion of the Event Horizon Telescope (EHT) will see the strategic addition of antennas at new geographical locations, transforming the sensitivity and imaging fidelity of the $\lambda \sim 1$\,mm EHT array. A possible South African EHT station would leverage a strong geographical advantage, local infrastructure, and radio astronomy expertise, and have strong synergies with the Africa Millimetre Telescope in Namibia. We assessed three South African candidate millimetre sites using climatological simulations and antenna sensitivity estimates, and found at least two promising sites. These sites are comparable to some existing EHT stations during the typical April EHT observing window and outperform them during most of the year, especially the southern hemisphere winter. The results suggest that a strategically placed South African EHT station will have a sizable, positive impact on next-generation EHT objectives and the resulting black hole imaging science.