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Étude et modélisation des noyaux actifs de galaxie les plus énergétiques avec le satellite Fermi

Abstract : Launched June 11 2008 by NASA, the LAT (Large Area Telescope) on board the \textit{Fermi} satellite opened a new window on the gamma-ray sky. With the capabilities of the LAT to detect photons in the energy range 200 MeV-300 GeV, it becomes possible to study Active Galactic Nuclei (AGN), especially the class of blazars and the most energetic of them : High frequency peaked BL Lac (HBL). The blazars are AGN with a jet pointing in the direction of the Earth. This thesis presents a systematic study of blazars, also detected by the Cherenkov observatories above 200 GeV, made with 5.5 months of data taken by the LAT. The comparison between the two energy bands is used to study the distribution of emitting particles and the effect of the photons propagation from the source to the observer. A electromagnetic emission model of the jetted plasma called synchrotron self-Compton (SSC) is described and used to reproduce the spectra of the HBL PKS 2155-305 and PG 1553+113. The results indicate that the Klein-Nishina effect reducing the cross section of the Compton scattering process play a important role. A long-term study (approximately 1 year) on PKS 2155-305 in X-rays and gamma rays is described. Conducted with the RXTE satellite (X-rays) and the LAT, this is the longest joint observation campaign to date. The temporal and spectral properties of the source are described with a time-dependent SSC model.
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https://pastel.archives-ouvertes.fr/pastel-00521741
Contributor : David Sanchez <>
Submitted on : Tuesday, September 28, 2010 - 2:38:36 PM
Last modification on : Wednesday, March 27, 2019 - 4:40:12 PM
Long-term archiving on: : Thursday, October 25, 2012 - 4:10:10 PM

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David Sanchez. Étude et modélisation des noyaux actifs de galaxie les plus énergétiques avec le satellite Fermi. Cosmologie et astrophysique extra-galactique [astro-ph.CO]. Ecole Polytechnique X, 2010. Français. ⟨pastel-00521741⟩

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