Discovery of a bright radio transient in M 82: a new radio supernova? A. Brunthaler, K. M. Menten, M. J. Reid, C. Henkel, G. C. Bower and H. Falcke A&A, 499 2 (2009) L17-L20 Published online: 29 April 2009 DOI: 10.1051/0004-6361/200912327