Long quasi-periodic oscillations of sunspots and nearby magnetic structures V. Smirnova, A. Riehokainen, A. Solov’ev, J. Kallunki, A. Zhiltsov and V. Ryzhov A&A, 552 (2013) A23 Published online: 18 March 2013 DOI: 10.1051/0004-6361/201219600