High energy gamma ray emission and multi-wavelength view of the AGN PKS 0537-441
Abstract: This thesis describes the analysis of Very High Energy (VHE) emission from the Active Galactic Nucleus PKS 0537-441. It also aims to put the results in a wider context by implementing previous work done on this source. The data chosen for the analysis is provided by the Fermi-LAT satellite and covers the energy range between 300 MeV and 300 GeV. Initially a lightcurve of the received ﬂux from the source was generated, containing data from August 2008 to April 2017, with a mean ﬂux of 4∗10−8 photons per second per squared centimeter. The lightcurve contained sections of diﬀerent ﬂux intensities giving periods of special interest, such as a ﬂaring period at August 2008 to August 2011, an enormous ﬂare at April 2010 and a less active period between April 2013 - January 2016 that could be identiﬁed for further investigations. The diﬀerences in observed ﬂux over time was tested and PKS 0537-441 was found to be a signiﬁcantly variable source. Spectral Energy Distribution (SED) analysis was performed over both the entire period as well as over the selected subperiods and ﬁtted against models using the tools provided by the Fermi Science Support Center (FSSC). The models used in the ﬁtting was PowerLaw2, LogParabola and PLSuperExpCutoﬀ and the best ﬁt for the data was obtained from the PLSuperExpCutoﬀ, except for the less intense period where the LogParabola gave the best ﬁt. The result from the SED analysis was integrated with results from previous work done on the source, ranging over multiple wavelengths in order to get a SED which spanned over the entire electromagnetic spectrum. Finally, modeling of this multi wavelength SED was performed in order to obtain parameters for the physical processes involved in the creation of the radiation received from PKS 0537-441.
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