Aşırı parlak x-ışını kaynağı swift J0243.6+6124'ün tayfsal analizi

In this thesis, the spectral analysis on the first galactic ultraluminous X-ray pulsar Swift J0243.6+6124 has been carried out. This peculiar object has been firstly observed by Swift observatory during its outburst in the late 2017 – early 2018 and it is a part of a Be/X-ray binary system. Observations obtained from NuSTAR observatory have been utilized in this study. The analysis showed that the source underwent drastic changes from the beginning of its outburst stage, during the peak of the outburst and after the outburst. The pulse-phase-resolved spectroscopy revealed that the source was accreting in two different regimes within the span of five observations – sub-critical and super-critical ones. The phase-dependent profiles of blackbody temperature and its normalization suggest that the source has a hot spot of a certain size which indicates the existence of a sub-critical accretion in pre- and post-outburst observations. It is also shown that the object also accretes in a clumpy way during the super-critical regime. The results of the analysis are consistent with the established theory and other publications, more clarity on the accretion details of the source during its outburst stage has been achieved as a result of this thesis study.