title: On the Origin of the Unusually Hard gamma-ray Spectra of TeV Blazars
creator: Zacharopoulou, Olga
subject: ddc-520
subject: 520 Astronomy and allied sciences
description: The observed VHE spectra from blazars may be significantly modified due to interactions  of $gamma$-rays with intergalactic radiation fields. To study the emission production in these kind of objects, one should reconstruct the intrinsic spectra using an Extragalactic Background Light (EBL) model. Interestingly,  this correction often leads to unusually hard spectra. In this dissertation we take into account the EBL absorption by using different models to reconstruct blazars' spectra and we study  the formation of broad-band spectra in the framework of a proton synchrotron scenario with non-negligible gamma-gamma absorption in the production region. This internal absorption leads to rather hard VHE spectra. Moreover, a significant fraction of the energy absorbed in the VHE band may be transferred into secondary electron-positron pairs providing an additional radiation channel that explains the observed radiation in the Optical/X-ray regimes. In order to demonstrate the potential of the model, we model two relatively distant blazars, 1ES 0229+200 (z=0.1396) and 3C 66A (z=0.444). In addition, we perform numerical simulations using relativistic MHD in time variable injection setup, in an attempt to understand better the conditions under which radiation is produced in relativistic jets.
date: 2010
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/11452/1/Zacharopoulou_thesis.pdf
identifier: DOI:10.11588/heidok.00011452
identifier: urn:nbn:de:bsz:16-opus-114523
identifier:   Zacharopoulou, Olga  (2010) On the Origin of the Unusually Hard gamma-ray Spectra of TeV Blazars.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/11452/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng