Very high energy emission from passive supermassive black holes [Elektronische Ressource] / put forward by Giovanna Pedaletti

Dissertationsubmitted to theCombined Faculties of the Natural Sciences and Mathematicsof the Ruperto-Carola-University of Heidelberg, Germanyfor the degree ofDoctor of Natural SciencesPut forward byGiovanna Pedalettiborn in: Fano, ItalyndOral examination: 22 October, 2009Very High Energy Emission from PassiveSupermassive Black HolesReferees: Prof. Dr. Stefan J. WagnerProf. Dr. John G. KirkAbstractThe H.E.S.S. experiment, an array of four Imaging Cherenkov Telescopes, widened the horizon ofVery High Energy (VHE) astronomy. Its unprecedented sensitivity is well suited for the study ofnew classes of expected VHE emitters, such as passive galactic nuclei that are the main focus ofthe workpresentedinthis thesis. Accelerationofparticlesupto UltraHighEnergiesisexpectedinthe magnetosphere of supermassive black holes (SMBH). The radiation losses of these acceleratedparticlesareexpectedtoreachtheVHEregimeinwhichH.E.S.S.operates. Predictedfluxesexceedthe sensitivity of the array. However, strong photon fields in the surrounding of the accelerationregion might absorb the produced radiation. Therefore observations focus on those galactic nucleithatareunderluminousatlowerphotonenergies. ThisworkpresentsdatacollectedbytheH.E.S.S.telescopes on the test candidate NGC 1399 and their interpretation.