Which two astronomers discovered Sagittarius A* in 1974?

Which two astronomers discovered Sagittarius A* in 1974? Bruce Balick and Robert Brown made the discovery.

The compact radio source was identified on February 13 and 15, 1974, at the center of the Milky Way. Their work used radio observations to distinguish this intense, tiny source from the broader region known as Sagittarius A. The object is now understood to be associated with the Milky Way’s supermassive black hole.

A common mix-up is Karl Jansky, who detected radio emission from the direction of Sagittarius in 1933. Jansky’s pioneering observation helped reveal the Galactic Center, but it was not the discovery of Sagittarius A*. Another source of confusion is the name: Sagittarius A is the larger radio complex, while the asterisk identifies its compact central component.

The name Sagittarius A* was assigned in 1982 by Robert Brown. Later observations of stars, especially S2, established that the compact object contains roughly four million solar masses and is a black hole.