Sgr A* Black Hole (Event Horizon Telescope)

On May 12 2022 the Event Horizon Telescope (EHT) team announced the first ever image

of the massive blackhole (BH) at the center of the (our) Milky Way (MW) galaxy in a press conference. This image follows the EHT 2019 release of the BH image from a remote galaxy called M87. The unprecedented angular resolution of EHT is comparable to resolving an orange on the moon. It is enabled by combining data from radio telescopes all over the world.

 

The existence of the MW BH and its mass, of about 4 million times that of the sun, was confirmed from the orbits of stars around this dark spot on the sky known to astronomer as Sgr A*. This discovery led to the Nobel prize of physics being awarded in 2020 to Andrea Ghez and Reinhard Genzel. However, EHT obtained the first direct image of Sgr A* resolving the radio emission (230 GHz) around it. The physical mechanisms behind this radio emission, and the dynamics of gas right next to the BH is not well understood. The EHT images will likely shed new light on this fascinating topic.