HST observations rule out the association between Cir X-1 and SNR G321.9-0.3 R. P. Mignani, A. De Luca, P. A. Caraveo and I. F. Mirabel A&A, 386 2 (2002) 487-491 Published online: 15 May 2002 DOI: 10.1051/0004-6361:20020224