[1] Univ Tubingen, Inst Theoret Phys, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany
[2] Tomsk State Univ, Dept Phys, Tomsk 634050, Russia
[3] Tomsk Polytech Univ, Dept Math Phys, Lenin Ave 30, Tomsk 634050, Russia
[4] Univ Tecn Federico Santa Maria, Dept Fis, Casilla 110-5, Valparaiso, Chile
[5] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso CCTVal, Casilla 110-5, Valparaiso, Chile
[6] Univ Valparaiso, Inst Fis & Astron, Ave Gran Bretana 1111, Valparaiso, Chile
[7] Ctr Astrofis Valparaiso, Ave Gran Bretana 1111, Valparaiso, Chile