REPRODUCTION AND ANALYSIS OF OPTICAL - GAMMA RAY SPECTRAL ENERGY DISTRIBUTION (SED) OF BLAZAR OJ 287 USING SWIFT AND FERMI DATA
OJ 287 is a blazar that has 12 year optical outburst cycle with a double peak strucure in each cycle. OJ 287 is currently modeled as binary supermassive black holes at the center of a galaxy at a distance of 3.5 billion light years. The objectives of this Final Project are: 1) study the high energy...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/39306 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | OJ 287 is a blazar that has 12 year optical outburst cycle with a double peak strucure in each cycle. OJ 287 is currently modeled as binary supermassive black holes at the center of a galaxy at a distance of 3.5 billion light years. The objectives of this Final Project are: 1) study the high energy astrophysical processes in blazar, 2) reproduce Spectral Energy Distribution (SED) of OJ 287 using Swift-UVOT, Swift-XRT, and Fermi-LAT data, 3) analyze the ?-ray spectra and SED of OJ 287. The observation data of OJ 287 in this Final Project was divided into two conditions, namely non-outburst (2008-2016) and outburst (2016/2017).
Blazar is a type of Active Galactic Nucleus (AGN) in which the jet direction is perpendicular or almost perpendicular to the observer's sky plane. Blazar can be used to study high energy astrophysical processes as well as distant universe. Blazar SED is characterized by two broad humps, interpreted as the result of synchrotron radiation at low energy and inverse-compton scattering at high energy. In addition, there exists a unique property in blazars SED in the form of blazar sequence which confirmed its existence by Fermi-LAT observations.
In non-outburst condition, the SED of OJ 287 from Swift and Fermi data show two broad humps similar to those SED of blazars in general. However, the SED during outburst show a change in shape as reported in a previous study by Valtonen et al. in 2012 that used outburst data in 2005. In this Final Project, logparabola model commonly used to model non-thermal processes in ? ray energy range in blazars. The differences in parameter values of the ? ray spectral model in outburst and non-outburst conditions indicate different physical processes in both conditions.
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