A multi-wavelength investigation of the non-thermal radio emitting O-star 9 Sgr G. Rauw, R. Blomme, W. L. Waldron, M. F. Corcoran, J. M. Pittard, A. M. T. Pollock, M. C. Runacres, H. Sana, I. R. Stevens and S. Van Loo A&A, 394 3 (2002) 993-1008 Published online: 21 October 2002 DOI: 10.1051/0004-6361:20020926