Asymmetry

Galaxy

Computer science

Optics

Telescope

Astrophysics

Quantum mechanics

Brightness

Supermassive black hole

Psychotherapist

Shadow (psychology)

Artificial intelligence

Psychology

Physics

The Astrophysical Journal Letters

We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ~40 micro-as, consistent with the size and shape of the lensed photon orbit encircling the "shadow" of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others' work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use wh...

First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole