Monitoring dusty sources in the vicinity of Sagittarius A* F. Peißker, S. E. Hosseini, M. Zajaček, A. Eckart, R. Saalfeld, M. Valencia-S., M. Parsa and V. Karas A&A, 634 (2020) A35 Published online: 04 February 2020 DOI: 10.1051/0004-6361/201935953