Doeleman founded and directs the Event Horizon Telescope, assembling a global mm-wavelength VLBI network to image the immediate environments of supermassive black holes at horizon-scale resolution — an astronomy pivot whose entire scientific case rests on pushing angular resolution to its fundamental (diffraction/baseline) limit via a globally distributed, highly complex sensor array.

Johnson studies neutron stars and black holes via extreme-resolution VLBI imaging, including direct observation of magnetic fields and orbital dynamics near black-hole event horizons as part of the Event Horizon Telescope collaboration, pushing spatial resolution to the horizon scale.

Markoff studies the extreme physics of accretion and jet formation around black holes of all scales, combining multi-wavelength observations with computational simulations; she is a founding member of the Event Horizon Telescope collaboration that produced the first black hole images, and co-leads a new EHT station in Namibia.