2251+158 (3C 454.3): detection of an arc-like structure on parsec scales S. Britzen, Shan-Jie Qian, A. Witzel, T. P. Krichbaum, M. Aller, H. Aller, O. Kurtanidze, S. Vercellone and G. M. Richter A&A, 557 (2013) A37 Published online: 23 August 2013 DOI: 10.1051/0004-6361/201220147