What is the name of the black hole at the centre of the Milky Way?

The black hole at the centre of the Milky Way is called Sagittarius A*.

Sagittarius A*, pronounced “Sagittarius A-star,” is a supermassive black hole located in the direction of the constellation Sagittarius. It lies about 26,000 light-years from Earth and has a mass of roughly 4.3 million Suns. Its presence is inferred from the rapid orbits of stars around an apparently invisible, extremely compact object.

The star S2 is especially important. It completes an elongated orbit around Sagittarius A* in about 16 years and has been observed passing close to the black hole. Measurements of S2’s motion provide strong evidence for the black hole’s mass and test predictions of general relativity.

In 2022, the Event Horizon Telescope collaboration released the first direct image of the shadow of Sagittarius A*. The orange ring-like emission comes from hot gas and light bent by gravity; the black hole itself is dark because light cannot escape from inside its event horizon.