EXPLORING X-RAY SCALING METHODS FOR DETERMINING BLACK HOLE MASS IN X-RAY BINARY SYSTEMS USING NUSTAR MISSION DATA

• Main Author: Sekar Annisa, Vanda
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81756
• Institution: Institut Teknologi Bandung

Evidence for the presence of black holes in X-ray binary systems is often based on mass estimates derived from orbital motion analyses. The information required for orbital motion analysis is difficult to obtain when the normal stars in these systems are very faint. Therefore, an alternative mass determination method that does not rely on observations of normal stars in X-ray binary systems is required. In this Final Project, an alternative mass determination method will be reviewed, namely the X-ray scaling method. This method uses the correlation between the photon index and the normalization of the X-ray radiation component modeled by a Bulk Motion Comptonization (BMC) model. The mass determination method utilizes X-ray observational data from the NuSTAR mission in the 3 ? 20 keV energy range. This method has been explored and applied to determine the masses of three black holes, namely GS 1354-64, GRS 1915+105, and MAXI J1820+070. However, for the other two objects, 4U 1543-475 and V4641 Sgr, the results obtained are not sufficient for further analysis. This is because not all of the available observational data can be used to construct the scaling curves. The processes occurring in the data are dominated by thermal emission that produces a photon index of ? > 3. Therefore, to achieve optimal scaling results, data with photon indices that are outside the scope of the reference object’s scaling curve are ignored. Not all reference objects can produce mass values that correspond to the dynamical masses of the three objects. The best black hole mass values obtained by the X-ray scaling method include GS 1354-64 with 27.86 ± 15.28M?, GRS 1915+105 with 10.78M?, and MAXI J1820+070 with 8.11 ± 8.54M?. This shows that the X-ray scaling method needs to be investigated more deeply regarding the selection criteria of reference objects that are suitable for black hole X-ray binaries.