Institution: | 1. Astronomical Institute, Faculty of Mathematics and Physics, Charles University Prague, CZ-180 00 Praha 8, V Hole?ovi?kách 2, Czech Republic;2. Astronomical Institute, Academy of Sciences, Fri?ova 298, CZ-251 65, Czech Republic;3. Research Centre for Theoretical Physics and Astrophysics, Institute of Physics, Silesian University in Opava, Bezru?ovo nám. 13, CZ-746 01 Opava, Czech Republic |