STUDY OF X-RAY SPECTRUM EVOLUTION IN THE OUTBURST PHASE OF THE BLACK HOLE X-RAY BINARY TRANSIENT MAXI J1820+070 USING SWIFT/XRT MISSION DATA

• Main Author: Gading Nur Fadhilah, Aulia
• Format: Final Project
• Language: Indonesia
• Subjects: Astronomi
• Online Access: https://digilib.itb.ac.id/gdl/view/73582
• Institution: Institut Teknologi Bandung

The discovery of the Sco X-1 as cosmic X-ray source paved the way for the discovery of various other X-ray sources, including the Black Hole X-ray Binary (BHXB). Most of the BHXBs have been found in our galaxy exhibit significant variations in intensity called transient sources. For this source, a sudden, sharp increase in intensity is known as an outburst. The increase in flux in an outburst event can be hundreds of times in a relatively short period of time, then the source returns to the same flux state as before the outburst event occured. The X-ray emissions produced at BHXB led to understanding the existence of a very powerful energy-generating mechanism, namely the accretion process. In general, the physical process of the accretion disk can be explained by the standard disk theory proposed by Shakura and Sunyaev in 1973. However, the complexity of the data due to the contribution of the black hole's environment makes it impossible to fully explain the physical processes. Therefore, it is necessary to carry out further studies on various spectral states and their evolution. In this final project, the characteristics and evolution of the X-ray spectrum of the MAXI J1820+070 transient BHXB in the outburst phase are studied using observational data from the Swift/XRT mission. There are 22 observation datas used to obtain the spectra. The results show that the observation of two outbursts has been confirmed, with the second outburst experiencing a hard-to-soft transition on the spectra with entering a thermal-dominant state at the peak of the outburst. The physical processes that occur in the MAXI J1820+070 environment can be predicted in line with the evolution of the radius of the innermost disk and the relationship of luminosity to the temperature by considering the assumption that a rotating black hole applies.