The nature and kinematics of the Northern Arm cloud of Sgr A West suggest that it once was a clump in the CND, which fell due to some perturbation, perhaps the supernova explosion responsible for Sgr A East.
Sifat dan kinematika dari awan Lengan Utara Sgr A Barat menunjukkan bahwa dahulu merupakan awan CND, yang ambruk karena beberapa gangguan, diantaranya ledakan supernova Sgr A Timur.