[1] Ctr Theoret Phys, Al Lotnikow 32-46, PL-02668 Warsaw, Poland
[2] Natl Ctr Nucl Res, Ul A Soltana 7, PL-05400 Otwock, Poland
[3] INAF Ist Astrofis Spaziale & Fis Cosm Milano, Via Bassini 15, I-20133 Milan, Italy
[4] Jagiellonian Univ, Astron Observ, Orla 171, PL-30001 Krakow, Poland