First M87 Event Horizon Telescope Results. II. Array and Instrumentation

Understand

The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth.

• At a nominal operating wavelength of ~1.3 mm, EHT angular resolution (lambda/D) is ~25 micro-as, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons.
• With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary.
• In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance.